JP2731422B2 - Glass for near infrared absorption filter - Google Patents
Glass for near infrared absorption filterInfo
- Publication number
- JP2731422B2 JP2731422B2 JP1152913A JP15291389A JP2731422B2 JP 2731422 B2 JP2731422 B2 JP 2731422B2 JP 1152913 A JP1152913 A JP 1152913A JP 15291389 A JP15291389 A JP 15291389A JP 2731422 B2 JP2731422 B2 JP 2731422B2
- Authority
- JP
- Japan
- Prior art keywords
- glass
- infrared absorption
- near infrared
- absorption filter
- present
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C3/00—Glass compositions
- C03C3/12—Silica-free oxide glass compositions
- C03C3/16—Silica-free oxide glass compositions containing phosphorus
- C03C3/19—Silica-free oxide glass compositions containing phosphorus containing boron
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、近赤外線領域、特に波長800〜1000nmの光
を効率的に吸収し、尚かつ可視域において高い透過率を
有するフィルタ用ガラスに関するものである。Description: TECHNICAL FIELD The present invention relates to a filter glass that efficiently absorbs light in the near-infrared region, particularly a wavelength of 800 to 1000 nm, and has a high transmittance in the visible region. is there.
本発明のフィルタガラスは、主にカラー撮影機器にお
ける受光素子の感度補正用フィルタなどとして使用され
る。The filter glass of the present invention is mainly used as a filter for correcting the sensitivity of a light receiving element in a color photographing device.
従来の技術 カラー撮影機器に使用される撮像管あるいは固体撮像
素子の分光感度は可視域から近赤外域の広い範囲にわた
っている。このため近赤外域の800〜900nmを吸収し可視
域を透過して通常の視感度に補正する近赤外吸収フィル
タは必要欠くべからざる光部品となっている。このよう
なフィルタ用のガラスは、800nm以上の波長域における
吸収係数が大きく、400〜700nmの波長域においては高い
透過性を持たなければならない。そして、このようなガ
ラスはリン酸系ガラスにCuOを添加することによって得
られる。すなわち、波長800nm付近に吸収帯を持つCu2+
がP2O5を主成分としたガラス中に存在した場合、800〜1
000nmの波長域の光を十分に吸収し、波長500nmを中心と
した可視域において高い透過率を有するガラスとなる事
が知られている。しかしながら、このガラスは吸湿性の
強いP2O5から形成されているため通常の使用に対して十
分な耐水性、耐候性を得ることが非常に困難で、長期間
使用するとガラス表面が変質し、光学的特性が劣化す
る。特公昭60−49142号公報及び特公昭63−25245号公報
などに、これらの耐水性、耐候性を改良したガラスがあ
る。2. Description of the Related Art The spectral sensitivity of an imaging tube or a solid-state imaging device used in a color photographing device ranges from a visible region to a near-infrared region. For this reason, a near-infrared absorption filter that absorbs 800 to 900 nm in the near-infrared region and transmits through the visible region to correct for normal visibility is an indispensable optical component. Such a filter glass has a large absorption coefficient in a wavelength region of 800 nm or more, and must have high transmittance in a wavelength region of 400 to 700 nm. Such a glass is obtained by adding CuO to a phosphate glass. That is, Cu 2+ which has an absorption band near the wavelength of 800 nm
Is present in the glass containing P 2 O 5 as the main component, 800 to 1
It is known that a glass that sufficiently absorbs light in a wavelength range of 000 nm and has a high transmittance in a visible range centered at a wavelength of 500 nm is obtained. However, the glass is sufficient water resistance for normal use because they are formed from a strong P 2 O 5 hygroscopicity, weather resistance is very difficult to obtain, the glass surface degenerated a long period of use And the optical characteristics are degraded. JP-B-60-49142 and JP-B-63-25245 disclose glasses having improved water resistance and weather resistance.
発明が解決しようとする課題 一般にガラスの化学的耐久性を向上させるためには、
基礎ガラス組成に化学的耐久性が良好で、ガラス構造の
一部を形成しうる化合物を導入すればよいことが知られ
ている。例えば、Al2O3はこのような場合非常に効果的
である。またこのことと同時にガラス組成中のアルカリ
成分の含有量を少なくすることも化学的耐久性の向上に
効果がある。前記公告公報においても、このような手法
が用いられている。しかしながらAl2O3を大量に導入し
たり、また、アルカリ成分の含有量を極端に少なくする
ため、溶融温度が高くなり、ガラスの脱泡、均質化が難
しくなる。一方、このガラス中に含まれるCu2+は高温下
でCu+に変化する傾向があり、その場合、近赤外領域に
おける吸収係数が小さくなり、十分な光学的性能が得ら
れなくなる。つまり、化学的耐久性を向上させるため
に、溶融温度が高いガラス組成を用いる従来の手法を使
用した場合、Cu2+がCu+に変化してしまう傾向があるた
めに、光学的特性を劣化させることになる。Problems to be Solved by the Invention Generally, in order to improve the chemical durability of glass,
It is known that a compound having good chemical durability and capable of forming a part of a glass structure may be introduced into a base glass composition. For example, Al 2 O 3 is very effective in such a case. At the same time, reducing the content of the alkali component in the glass composition is also effective in improving the chemical durability. Such a technique is also used in the above publication. However, since a large amount of Al 2 O 3 is introduced or the content of the alkali component is extremely reduced, the melting temperature increases, and it becomes difficult to defoam and homogenize the glass. On the other hand, Cu 2+ contained in this glass tends to change to Cu + at a high temperature, in which case the absorption coefficient in the near-infrared region becomes small and sufficient optical performance cannot be obtained. In other words, when the conventional method using a glass composition with a high melting temperature is used to improve the chemical durability, optical properties are degraded because Cu 2+ tends to change to Cu +. Will be.
また、特公昭63−25245号公報には、SiO2、SnO2を添
加する方法が述べられているが、SiO2は、近赤外におい
て吸収係数を小さくし、SnO2は、可視域において透過率
を下げる。また両成分とも、リン酸系ガラス中に入れた
場合ガラスを失透し易くする傾向がある。Japanese Patent Publication No. 63-25245 discloses a method of adding SiO 2 and SnO 2 , but SiO 2 has a small absorption coefficient in the near infrared and SnO 2 transmits in the visible region. Decrease rate. In addition, both components tend to devitrify the glass when placed in phosphate glass.
したがって本発明においては、光学的特性に影響を及
ぼさないような比較的低い温度で溶融が可能で、SnO2、
SiO2などを含まず、十分な化学的耐久性を持つガラスを
新たに提供することを目的とする。Therefore, in the present invention, it is possible to melt at a relatively low temperature that does not affect the optical properties, SnO 2 ,
An object of the present invention is to newly provide glass having sufficient chemical durability without containing SiO 2 or the like.
課題を解決するための手段 本発明者は、前述のような点を考慮して、鋭意研究し
た結果アルカリ酸化物を含むリン酸塩系ガラスにおい
て、十分な性能を有する近赤外吸収フィルタ用ガラス組
成を見出した。すなわち重量百分率でP2O5が65.0〜75.0
％、Al2O3が11.0〜14.0％、B2O3が０〜4.0％、K2Oが7.0
〜9.0％、MgOが2.0〜6.0％、ZnOが０〜4.0％、CuOが1.5
〜4.0％の組成範囲にあることを特徴とする近赤外吸収
フィルタ用ガラスである。本発明のガラス組成を前記の
範囲に限定した理由は次に示すとおりである。Means for Solving the Problems The present inventor has taken the above-mentioned points into consideration, and as a result of intensive research, a phosphate glass containing an alkali oxide, a glass for a near infrared absorption filter having a sufficient performance. The composition was found. That is P 2 O 5 in a weight percentage from 65.0 to 75.0
%, Al 2 O 3 is 11.0 to 14.0%, B 2 O 3 is 0 to 4.0%, K 2 O is 7.0
~ 9.0%, MgO 2.0 ~ 6.0%, ZnO 0 ~ 4.0%, CuO 1.5
A glass for a near-infrared absorption filter, which is characterized by having a composition range of about 4.0%. The reason for limiting the glass composition of the present invention to the above range is as follows.
P2O5は、ガラス網目を構成するための主成分である
が、65％未満では近赤外域における吸収係数が小さく、
75％を超えると長期間の使用に耐えうる耐水性、耐候性
を得ることが困難になる。P 2 O 5 is the main component for constituting the glass network, but if it is less than 65%, the absorption coefficient in the near infrared region is small,
If it exceeds 75%, it becomes difficult to obtain water resistance and weather resistance that can withstand long-term use.
Al2O3は、耐水性、耐候性を向上させるためには有効
な成分であるが、11％未満では長期間の使用に耐えうる
耐水性、耐候性を得ることが困難になり、14％を超える
と硝子の溶融温度が高くなり、本発明の目的である低温
での溶融が不可能となる。Al 2 O 3 is an effective component for improving water resistance and weather resistance, but if it is less than 11%, it becomes difficult to obtain water resistance and weather resistance that can withstand long-term use, and 14% When the temperature exceeds the above range, the melting temperature of the glass increases, and the melting at a low temperature, which is the object of the present invention, becomes impossible.
B2O3は、ガラスの安定化に有効な成分であるが、４％
を超えるとガラスの耐候性が著しく悪くなる。B 2 O 3 is an effective ingredient for stabilizing glass, but 4%
If it exceeds 300, the weather resistance of the glass will be significantly deteriorated.
K2Oは、３％未満ではガラスの溶融温度が高くなり、
８％を超えると耐水性、耐候性ともに著しく悪くなる。If K 2 O is less than 3%, the melting temperature of the glass increases,
If it exceeds 8%, both the water resistance and the weather resistance are remarkably deteriorated.
MgOは、２％未満の場合、長期間の使用に耐えうる耐
水性、耐候性が得られず、６％を超えるとガラスの溶融
温度が高くなり、低温でのガラスの溶融が困難になる。If MgO is less than 2%, water resistance and weather resistance that can withstand long-term use cannot be obtained, and if it exceeds 6%, the melting temperature of the glass increases, making it difficult to melt the glass at low temperatures.
ZnOは、４％を超えるとガラスが失透投し易くなる。 If ZnO exceeds 4%, the glass tends to be devitrified and thrown.
CuOは1.5％未満では波長800〜1000nmにおいて十分な
吸収係数が得られず、4.0％を超えると可視域において
高い透過率が得られない。If CuO is less than 1.5%, a sufficient absorption coefficient cannot be obtained at a wavelength of 800 to 1000 nm, and if it exceeds 4.0%, high transmittance cannot be obtained in the visible region.
本発明によると前述の組成範囲にあるガラスは、近赤
外領域における十分大きな吸収係数と可視領域における
高い透過率を有し、かつ化学的耐久性がきわめて良好な
近赤外吸収フィルタ用ガラスである。According to the present invention, the glass having the above composition range has a sufficiently large absorption coefficient in the near infrared region and a high transmittance in the visible region, and is a glass for a near infrared absorption filter having extremely good chemical durability. is there.
実施例 次に本発明の実施例を第１表に示す。表中のガラス組
成はすべて重量百分率で示し、耐水性は日本光学硝子工
業会規格のガラスの化学的耐久性（粉末法）の測定によ
る級分類で示す。温度は、ガラス溶融時の最高温度、T
500は波長500nm、T700は波長700nmにおける厚さ1mmでの
透過率である。EXAMPLES Next, examples of the present invention are shown in Table 1. All the glass compositions in the table are shown by weight percentage, and the water resistance is shown by the classification by measuring the chemical durability (powder method) of the glass according to the Japan Optical Glass Industrial Association standard. The temperature is the maximum temperature when melting the glass, T
500 is the transmittance at a wavelength of 500 nm and T 700 is the transmittance at a wavelength of 700 nm at a thickness of 1 mm.
本発明のフィルタ用ガラスは、所定の酸化物ガラスが
得られるように各成分の原料として、おのおの相当する
酸化物、水酸化物、炭酸塩、硝酸塩等を使用し、ガラス
重量で150gとなるように所定の割合で秤量し、十分混合
した後白金製の坩堝内に投入して電気炉内で、950℃〜1
150℃で８〜15時間で溶融、撹拌、清澄を行なった後、
金型内に鋳込み徐冷して得られた。またCu2+を得るため
に溶融、清澄は大気中で行なった。 The filter glass of the present invention uses a corresponding oxide, hydroxide, carbonate, nitrate or the like as a raw material of each component so that a predetermined oxide glass is obtained, and the glass weight is 150 g. Weighed at a predetermined ratio, mixed well, and then put into a platinum crucible and placed in an electric furnace at 950 ° C to 1
After melting, stirring and refining at 150 ° C for 8 to 15 hours,
It was cast in a mold and cooled slowly. Melting and fining were performed in the air to obtain Cu 2+ .
耐水性、透過率は徐冷後に、得られたガラスを所望の
形に加工あるいは研磨して試料とし、測定した。The water resistance and the transmittance were measured after slow cooling, and the obtained glass was processed or polished into a desired shape to obtain a sample.
本発明において得られた、近赤外吸収フィルタ用ガラ
スの分光透過率曲線を第１図に示した。なお、図中にお
いて、曲線Ａは実施例２、曲線Ｂは実施例１、曲線Ｃは
比較例９のそれぞれの分光透過率曲線である。FIG. 1 shows the spectral transmittance curve of the glass for a near-infrared absorption filter obtained in the present invention. In the drawing, curve A is the spectral transmittance curve of Example 2, curve B is the spectral transmittance curve of Example 1, and curve C is the spectral transmittance curve of Comparative Example 9.
発明の効果 本発明によるCuOを添加したリン酸塩系ガラスを母体
とする近赤外吸収フィルタ用ガラスは、長期間の使用に
耐えうる耐水性、耐候性を持ち、かつ、近赤外域におけ
る効率のよい吸収係数と可視域における高い透過率を有
するので、カラー撮影機器に使用される撮像素子の分光
感度補正用フィルタとして有用である。Effect of the InventionNear-infrared absorption filter glass based on a phosphate glass to which CuO is added according to the present invention has water resistance and weather resistance that can withstand long-term use, and has an efficiency in the near infrared region. It has a good absorption coefficient and a high transmittance in the visible region, and thus is useful as a filter for correcting the spectral sensitivity of an image sensor used in a color photographing device.
第１図は、本発明ガラス及び従来ガラスの分光透過率曲
線である。FIG. 1 shows the spectral transmittance curves of the glass of the present invention and the conventional glass.
Claims (1)
が11.0〜14.0％、B2O3が０〜4.0％、K2Oが7.0〜9.0％、
MgOが2.0〜6.0％、ZnOが０〜4.0％、CuOが1.5〜4.0％か
らなるガラス組成を有する近赤外吸収フィルタ用ガラ
ス。1. A P 2 O 5 in a weight percentage 65.0~75.0%, Al 2 O 3
Is 11.0-14.0%, B 2 O 3 is 0-4.0%, K 2 O is 7.0-9.0%,
A glass for a near-infrared absorption filter having a glass composition of 2.0 to 6.0% MgO, 0 to 4.0% ZnO, and 1.5 to 4.0% CuO.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1152913A JP2731422B2 (en) | 1989-06-15 | 1989-06-15 | Glass for near infrared absorption filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1152913A JP2731422B2 (en) | 1989-06-15 | 1989-06-15 | Glass for near infrared absorption filter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0316933A JPH0316933A (en) | 1991-01-24 |
| JP2731422B2 true JP2731422B2 (en) | 1998-03-25 |
Family
ID=15550884
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1152913A Expired - Fee Related JP2731422B2 (en) | 1989-06-15 | 1989-06-15 | Glass for near infrared absorption filter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2731422B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2925799B2 (en) * | 1991-08-30 | 1999-07-28 | ホーヤ株式会社 | Optical filter structure for weather resistance tester and weather resistance tester |
| JP2510146B2 (en) * | 1993-02-08 | 1996-06-26 | 東芝硝子株式会社 | Near infrared cut filter glass |
| BE1009761A3 (en) * | 1995-10-30 | 1997-08-05 | Philips Electronics Nv | METHOD FOR MANUFACTURING OF A low-pressure mercury discharge lamp and low-pressure mercury discharge lamp, which is by a similar method to manufacture. |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5580737A (en) * | 1978-12-11 | 1980-06-18 | Toshiba Glass Co Ltd | Colored glass |
-
1989
- 1989-06-15 JP JP1152913A patent/JP2731422B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0316933A (en) | 1991-01-24 |
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