JP2019006643A - Optical glass - Google Patents
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- JP2019006643A JP2019006643A JP2017124828A JP2017124828A JP2019006643A JP 2019006643 A JP2019006643 A JP 2019006643A JP 2017124828 A JP2017124828 A JP 2017124828A JP 2017124828 A JP2017124828 A JP 2017124828A JP 2019006643 A JP2019006643 A JP 2019006643A
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- 239000005304 optical glass Substances 0.000 title claims abstract description 58
- 238000002834 transmittance Methods 0.000 claims abstract description 31
- 229910052788 barium Inorganic materials 0.000 claims abstract description 8
- 229910052712 strontium Inorganic materials 0.000 claims abstract description 8
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 8
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 7
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 7
- 239000011521 glass Substances 0.000 claims description 48
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 28
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 25
- 230000009477 glass transition Effects 0.000 claims description 24
- 229910018068 Li 2 O Inorganic materials 0.000 claims description 11
- 239000000463 material Substances 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 9
- 229910015902 Bi 2 O 3 Inorganic materials 0.000 claims description 7
- 229910021193 La 2 O 3 Inorganic materials 0.000 claims description 7
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 5
- 238000003426 chemical strengthening reaction Methods 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 238000005342 ion exchange Methods 0.000 description 15
- 238000002844 melting Methods 0.000 description 13
- 230000008018 melting Effects 0.000 description 13
- 238000000465 moulding Methods 0.000 description 13
- 239000002585 base Substances 0.000 description 9
- 230000007423 decrease Effects 0.000 description 9
- 238000004031 devitrification Methods 0.000 description 5
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 5
- 239000000203 mixture Substances 0.000 description 4
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- 230000008020 evaporation Effects 0.000 description 3
- 239000006060 molten glass Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 229910052709 silver Inorganic materials 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 206010040925 Skin striae Diseases 0.000 description 2
- 230000004075 alteration Effects 0.000 description 2
- 229910052793 cadmium Inorganic materials 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000004040 coloring Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 description 2
- 238000004659 sterilization and disinfection Methods 0.000 description 2
- 229910052777 Praseodymium Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910052794 bromium Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 235000010333 potassium nitrate Nutrition 0.000 description 1
- 239000004323 potassium nitrate Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 230000001954 sterilising effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Surface Treatment Of Glass (AREA)
- Glass Compositions (AREA)
Abstract
Description
本発明は光学ガラスに関するものである。 The present invention relates to an optical glass.
紫外線発光素子は、殺菌、消毒、浄水、センシング、樹脂硬化等の各種用途に用いられる。従来、紫外線発光素子として水銀灯が多く使用されてきたが、近年は、より環境負荷の少ないＬＥＤ（発光ダイオード）への転換が検討されつつある（例えば特許文献１参照）。 Ultraviolet light emitting elements are used for various applications such as sterilization, disinfection, water purification, sensing, and resin curing. Conventionally, mercury lamps have been frequently used as ultraviolet light-emitting elements, but in recent years, conversion to LEDs (light-emitting diodes) with less environmental load is being studied (for example, see Patent Document 1).
紫外線ＬＥＤには、光出射部分に光学ガラスが取り付けられることがある。当該光学ガラスは、紫外線ＬＥＤチップを保護するカバー部材としての機能を果たすため、機械的強度が要求される。また、紫外線ＬＥＤの用途により、当該光学ガラスに要求される機能（光の集光、拡大等）が異なるため、光学ガラスの形状は多種多様である。当該光学ガラスの材料として、例えば、概ね波長３５０ｎｍ以下の短波長域（深紫外域）において透過特性に優れた石英ガラスが用いられている。 In an ultraviolet LED, an optical glass may be attached to a light emitting portion. Since the optical glass functions as a cover member for protecting the ultraviolet LED chip, mechanical strength is required. Moreover, since the functions (light collection, expansion, etc.) required for the optical glass differ depending on the use of the ultraviolet LED, the shape of the optical glass is various. As the material of the optical glass, for example, quartz glass having excellent transmission characteristics in a short wavelength region (deep ultraviolet region) having a wavelength of approximately 350 nm or less is used.
しかしながら、シリカガラスはガラス転移点、軟化点が高いため、プレス成型性に劣り、所望の形状を得にくい、及び、機械的強度が不十分であり破損しやすいという問題があった。 However, since silica glass has a high glass transition point and softening point, it has a problem that it is inferior in press moldability, it is difficult to obtain a desired shape, and mechanical strength is insufficient and it is easily damaged.
本発明の目的は上記課題に鑑み、紫外線透過率が高く、プレス成型性に優れ、かつ、機械的強度が高い光学ガラスを提供することである。 In view of the above problems, an object of the present invention is to provide an optical glass having high ultraviolet transmittance, excellent press moldability, and high mechanical strength.
本発明の光学ガラスは、表面に圧縮応力層を有する光学ガラスであって、質量％で、ＳｉＯ２ ４０〜７５％、Ｂ２Ｏ３ ０〜３０％、Ａｌ２Ｏ３ ３〜１５％、ＲＯ ０．１〜１０％（ＲはＭｇ、Ｃａ、Ｓｒ、Ｂａ及びＺｎから選択される少なくとも１種）、Ｌｉ２Ｏ ０．１〜１０％、Ｎａ２Ｏ＋Ｋ２Ｏ ３〜２０％、ＺｒＯ２ ０〜３％、Ｆ２ ０〜５％を含有することを特徴とする。ここで、「Ｎａ２Ｏ＋Ｋ２Ｏ」とは、Ｎａ２Ｏ及びＫ２Ｏの含有量の合量を意味する。本発明では、紫外線透過率を高めるＳｉＯ２の含有量を４０質量％以上、紫外線透過率を低下させるＬｉ２Ｏの含有量を１０質量％以下、及び、Ｎａ２Ｏ＋Ｋ２Ｏの含有量を２０質量％以下に規制することにより高い紫外線透過率を達成している。また、ガラス転移点を低下させるＲＯ（ＲはＭｇ、Ｃａ、Ｓｒ、Ｂａ及びＺｎから選択される少なくとも１種）の含有量を０．１質量％以上、Ｌｉ２Ｏの含有量を０．１質量％以上、及び、Ｎａ２Ｏ＋Ｋ２Ｏの含有量を３質量％以上に規制することにより、優れたプレス成型性を達成している。さらに、表面に圧縮応力層を有しているため機械的強度に優れる。 The optical glass of the present invention is an optical glass having a compressive stress layer on the surface, and is in mass%, SiO 2 40 to 75%, B 2 O 3 0 to 30%, Al 2 O 3 3 to 15%, RO 0.1 to 10% (R is at least one selected from Mg, Ca, Sr, Ba and Zn), Li 2 O 0.1 to 10%, Na 2 O + K 2 O 3 to 20%, ZrO 2 0 It is characterized by containing ˜3% and F 2 0-5%. Here, “Na 2 O + K 2 O” means the total content of Na 2 O and K 2 O. In the present invention, the content of SiO 2 for increasing the ultraviolet transmittance is 40% by mass or more, the content of Li 2 O for decreasing the ultraviolet transmittance is 10% by mass or less, and the content of Na 2 O + K 2 O is 20%. High ultraviolet transmittance is achieved by controlling to less than mass%. Further, the content of RO (R is at least one selected from Mg, Ca, Sr, Ba and Zn) that lowers the glass transition point is 0.1 mass% or more, and the content of Li 2 O is 0.1. Excellent press moldability is achieved by regulating the content of Na 2 O + K 2 O to 3% by mass or more. Furthermore, since it has a compressive stress layer on the surface, it is excellent in mechanical strength.
本発明の光学ガラスは、さらに、質量％で、Ｌａ２Ｏ３＋Ｎｂ２Ｏ５＋Ｂｉ２Ｏ３＋ＷＯ３ ０〜０．０５％を含有することが好ましい。ここで、「Ｌａ２Ｏ３＋Ｎｂ２Ｏ５＋Ｂｉ２Ｏ３＋ＷＯ３」とは、Ｌａ２Ｏ３、Ｎｂ２Ｏ５、Ｂｉ２Ｏ３及びＷＯ３の含有量の合量を意味する。 The optical glass of the present invention preferably further contains La 2 O 3 + Nb 2 O 5 + Bi 2 O 3 + WO 3 0 to 0.05% by mass%. Here, “La 2 O 3 + Nb 2 O 5 + Bi 2 O 3 + WO 3 ” means the total content of La 2 O 3 , Nb 2 O 5 , Bi 2 O 3 and WO 3 .
本発明の光学ガラスは、さらに、質量％で、ＴｉＯ２ １００ｐｐｍ以下、Ｆｅ２Ｏ３ ５０ｐｐｍ以下を含有することが好ましい。 The optical glass of the present invention preferably further contains, by mass%, TiO 2 100 ppm or less and Fe 2 O 3 50 ppm or less.
本発明の光学ガラスは、屈折率（ｎｄ）が１．４５〜１．５５であることが好ましい。なお、「ｎｄ」は、ｄ線における屈折率である。 The optical glass of the present invention preferably has a refractive index (nd) of 1.45 to 1.55. “Nd” is the refractive index at the d-line.
本発明の光学ガラスは、ガラス転移点が５５０℃以下であることが好ましい。 The optical glass of the present invention preferably has a glass transition point of 550 ° C. or lower.
本発明の光学ガラスは、軟化点が７５０℃以下であることが好ましい。 The optical glass of the present invention preferably has a softening point of 750 ° C. or lower.
本発明の光学ガラスは、肉厚１ｍｍで、波長２７０ｎｍにおける光透過率が５０％以上であることが好ましい。 The optical glass of the present invention preferably has a thickness of 1 mm and a light transmittance of 50% or more at a wavelength of 270 nm.
本発明の光学ガラスは、肉厚１ｍｍで、波長３００ｎｍにおける光透過率が８０％以上であることが好ましい。 The optical glass of the present invention preferably has a thickness of 1 mm and a light transmittance of 80% or more at a wavelength of 300 nm.
本発明の光学ガラスは、プレス成型体であることが好ましい。 The optical glass of the present invention is preferably a press-molded body.
本発明の光学ガラスは、圧縮応力層の圧縮応力値が５０〜１０００ＭＰａ、圧縮応力層の厚みが１〜１００μｍであることが好ましい。ここで、「圧縮応力層の圧縮応力値」及び「圧縮応力層の厚み」は、表面応力計を用いて干渉縞の本数とその間隔を観察して算出したものである。 In the optical glass of the present invention, the compressive stress layer preferably has a compressive stress value of 50 to 1000 MPa, and the compressive stress layer has a thickness of 1 to 100 μm. Here, the “compressive stress value of the compressive stress layer” and the “thickness of the compressive stress layer” are calculated by observing the number of interference fringes and their intervals using a surface stress meter.
本発明の光学ガラスの製造方法は、質量％で、ＳｉＯ２ ４０〜７５％、Ｂ２Ｏ３ ０〜３０％、Ａｌ２Ｏ３ ３〜１５％、ＲＯ ０．１〜１０％（ＲはＭｇ、Ｃａ、Ｓｒ、Ｂａ及びＺｎから選択される少なくとも１種）、Ｌｉ２Ｏ ０．１〜１０％、Ｎａ２Ｏ＋Ｋ２Ｏ ３〜２０％、ＺｒＯ２ ０〜３％、Ｆ２ ０〜５％を含有するガラス母材をプレス成型し、プレス成型ガラスを得る工程、及び、化学強化法にて前記プレス成型ガラスの表面に圧縮応力層を形成する工程を含むことを特徴とする。 Method for producing an optical glass of the present invention, in mass%, SiO 2 40~75%, B 2 O 3 0~30%, Al 2 O 3 3~15%, RO 0.1~10% (R is Mg , Ca, Sr, Ba and Zn), Li 2 O 0.1 to 10%, Na 2 O + K 2 O 3 to 20%, ZrO 2 0 to 3%, F 2 0 to 5% And a step of obtaining a press-molded glass by press-molding a glass base material containing, and a step of forming a compressive stress layer on the surface of the press-molded glass by a chemical strengthening method.
本発明によれば、紫外線透過率が高く、プレス成型性に優れ、かつ、機械的強度が高い光学ガラスを提供することができる。 According to the present invention, it is possible to provide an optical glass having high ultraviolet transmittance, excellent press moldability, and high mechanical strength.
本発明の光学ガラスは、表面に圧縮応力層を有する光学ガラスであって、質量％で、ＳｉＯ２ ４０〜７５％、Ｂ２Ｏ３ ０〜３０％、Ａｌ２Ｏ３ ３〜１５％、ＲＯ ０．１〜１０％（ＲはＭｇ、Ｃａ、Ｓｒ、Ｂａ及びＺｎから選択される少なくとも１種）、Ｌｉ２Ｏ ０．１〜１０％、Ｎａ２Ｏ＋Ｋ２Ｏ ３〜２０％、ＺｒＯ２ ０〜３％、Ｆ２ ０〜５％を含有することを特徴とする。 The optical glass of the present invention is an optical glass having a compressive stress layer on the surface, and is in mass%, SiO 2 40 to 75%, B 2 O 3 0 to 30%, Al 2 O 3 3 to 15%, RO 0.1 to 10% (R is at least one selected from Mg, Ca, Sr, Ba and Zn), Li 2 O 0.1 to 10%, Na 2 O + K 2 O 3 to 20%, ZrO 2 0 It is characterized by containing ˜3% and F 2 0-5%.
まず、ガラス組成を上記のように限定した理由を以下に示す。なお、各成分の含有量の説明において、特に断りのない限り、「％」は「質量％」を意味する。 First, the reason for limiting the glass composition as described above will be described below. In the description of the content of each component, “%” means “mass%” unless otherwise specified.
ＳｉＯ２は、紫外線透過率と耐候性を向上させ、また屈折率を低下させ、さらに液相粘度を高める成分である。ＳｉＯ２の含有量は４０〜７５％であり、４５〜７０％、特に５０〜６５％であることが好ましい。ＳｉＯ２の含有量が少なすぎると、屈折率を低下させることが困難になったり、紫外線透過率が低下する傾向がある。一方、ＳｉＯ２の含有量が多すぎると、ガラス転移点が上昇しプレス成型性が低下する傾向がある。また、ガラスの溶解性が悪化したり、ＳｉＯ２を含む失透物が析出しやすくなる。 SiO 2 is a component that improves ultraviolet transmittance and weather resistance, lowers the refractive index, and further increases the liquid phase viscosity. The content of SiO 2 is 40 to 75%, preferably 45 to 70%, particularly preferably 50 to 65%. When the content of SiO 2 is too small, or is difficult to reduce the refractive index, ultraviolet transmittance tends to decrease. On the other hand, if the content of SiO 2 is too large, the glass transition point rises press molding tends to decrease. Further, deteriorates the melting property of the glass, devitrification is likely to precipitate containing SiO 2.
Ｂ２Ｏ３は、イオン交換性能を高めることにより圧縮応力値を向上させ、また屈折率を低下させ、さらに耐候性を向上させる成分である。Ｂ２Ｏ３の含有量は０〜３０％であり、０．５〜２７．５％、１〜２５％、特に２．５〜２２％であることが好ましい。Ｂ２Ｏ３の含有量が多すぎると、ガラス転移点が上昇しプレス成型性が低下する傾向がある。また、成形時に蒸発しやすいため脈理が発生しやすくなる。さらに、紫外線透過率が低下しやすくなる。なお、イオン交換、圧縮応力値については後で詳述する。 B 2 O 3 is a component that improves the compression stress value by increasing the ion exchange performance, lowers the refractive index, and further improves the weather resistance. The content of B 2 O 3 is 0 to 30%, preferably 0.5 to 27.5%, 1 to 25%, particularly preferably 2.5 to 22%. If the B 2 O 3 content is too large, the glass transition point rises press molding tends to decrease. In addition, striae are likely to occur due to evaporation during molding. Furthermore, the ultraviolet transmittance tends to decrease. The ion exchange and compressive stress values will be described in detail later.
Ａｌ２Ｏ３は、イオン交換性能を向上させ、また屈折率を低下させ、さらに耐候性を向上させる成分である。Ａｌ２Ｏ３の含有量は３〜１５％であり、３．５〜１２．５％、４〜１０％、特に５〜９％であることが好ましい。Ａｌ２Ｏ３の含有量が少なすぎると、上記効果が得られにくくなる。一方、Ａｌ２Ｏ３の含有量が多すぎると、ガラス転移点が上昇しプレス成型性が低下する傾向がある。また、ガラスの溶解性が悪化したり、Ａｌ２Ｏ３を含む失透物が析出しやすくなる。 Al 2 O 3 is a component that improves ion exchange performance, lowers the refractive index, and further improves weather resistance. The content of Al 2 O 3 is 3 to 15%, preferably 3.5 to 12.5%, 4 to 10%, particularly preferably 5 to 9%. When the content of Al 2 O 3 is too small, the effect is difficult to obtain. On the other hand, when the content of Al 2 O 3 is too large, the glass transition point rises press molding tends to decrease. Further, it deteriorates the melting property of the glass, devitrification containing Al 2 O 3 is likely to precipitate.
ＳｉＯ２＋Ａｌ２Ｏ３の含有量は５５〜８０％、５７．５〜７７．５％、６０〜７５％、特に６２．５〜７２．５％であることが好ましい。ＳｉＯ２＋Ａｌ２Ｏ３の含有量が少なすぎると、屈折率が高くなりすぎたり、紫外線透過率が低下しやすくなる。一方、ＳｉＯ２＋Ａｌ２Ｏ３の含有量が多すぎると、ガラス転移点が上昇しプレス成型性が低下する傾向がある。なお、「ＳｉＯ２＋Ａｌ２Ｏ３」とは、ＳｉＯ２及びＡｌ２Ｏ３の含有量の合量を意味する。 The content of SiO 2 + Al 2 O 3 is 55 to 80%, 57.5 to 77.5%, 60 to 75%, particularly preferably 62.5 to 72.5%. When the content of SiO 2 + Al 2 O 3 is too small, or too high refractive index, ultraviolet transmittance tends to decrease. On the other hand, when the content of SiO 2 + Al 2 O 3 is too large, the glass transition point rises press molding tends to decrease. “SiO 2 + Al 2 O 3 ” means the total content of SiO 2 and Al 2 O 3 .
なお、ＳｉＯ２／Ｂ２Ｏ３は１０以下、７．５以下、５以下、４以下、特に３以下であることが好ましい。ＳｉＯ２／Ｂ２Ｏ３が大きすぎると、ガラスの溶解性が悪化し、ＳｉＯ２を含む失透物が析出しやすくなる。また、ＳｉＯ２／Ｂ２Ｏ３の下限は特に限定されないが、現実的には、１．４以上であることが好ましい。なお、「ＳｉＯ２／Ｂ２Ｏ３」とは、ＳｉＯ２の含有量をＢ２Ｏ３の含有量で除した値を指す。 Incidentally, SiO 2 / B 2 O 3 is 10 or less, 7.5 or less, 5 or less, 4 or less, and particularly preferably 3 or less. If SiO 2 / B 2 O 3 is too large, the solubility of the glass is deteriorated, and devitrified materials containing SiO 2 are likely to precipitate. Further, the lower limit of SiO 2 / B 2 O 3 is not particularly limited, but practically, it is preferably 1.4 or more. “SiO 2 / B 2 O 3 ” refers to a value obtained by dividing the content of SiO 2 by the content of B 2 O 3 .
また、ＳｉＯ２／Ａｌ２Ｏ３は１０以下、７．５以下、５以下、４以下、特に３以下であることが好ましい。ＳｉＯ２／Ａｌ２Ｏ３が大きすぎると、ガラスの溶解性が悪化し、ＳｉＯ２を含む失透物が析出しやすくなる。また、ＳｉＯ２／Ａｌ２Ｏ３の下限は特に限定されないが、現実的には、２．７以上であることが好ましい。なお、「ＳｉＯ２／Ａｌ２Ｏ３」とは、ＳｉＯ２の含有量をＡｌ２Ｏ３の含有量で除した値を指す。 Also, SiO 2 / Al 2 O 3 is 10 or less, 7.5 or less, 5 or less, 4 or less, and particularly preferably 3 or less. When the SiO 2 / Al 2 O 3 is too large, solubility of the glass is deteriorated, devitrification containing SiO 2 is likely to precipitate. Further, the lower limit of SiO 2 / Al 2 O 3 is not particularly limited, but in practice, it is preferably 2.7 or more. “SiO 2 / Al 2 O 3 ” refers to a value obtained by dividing the content of SiO 2 by the content of Al 2 O 3 .
ＲＯ（ＲはＭｇ、Ｃａ、Ｓｒ、Ｂａ及びＺｎから選択される少なくとも１種）は、ガラス転移点を低下させ、またガラスの高温粘性を低下させる成分である。ＲＯの含有量（合量）は０．１〜１０％であり、０．５〜９．５％、１〜９％、特に２〜８％であることが好ましい。ＲＯの含有量が少なすぎると、ガラス転移点を低下させることが困難になる。一方、ＲＯの含有量が多すぎると、失透傾向が強くなってガラス化しにくくなり、プレス成型する際にガラスがプレス金型に融着しやすくなる。また、イオン交換性能が低下しやすくなる。 RO (R is at least one selected from Mg, Ca, Sr, Ba and Zn) is a component that lowers the glass transition point and lowers the high temperature viscosity of the glass. The content (total amount) of RO is 0.1 to 10%, preferably 0.5 to 9.5%, 1 to 9%, and particularly preferably 2 to 8%. When there is too little content of RO, it will become difficult to reduce a glass transition point. On the other hand, if the RO content is too large, the tendency to devitrification becomes strong and it becomes difficult to vitrify, and the glass is likely to be fused to the press mold during press molding. In addition, the ion exchange performance tends to be lowered.
なお、ＲＯの各成分の含有量の範囲は以下の通りである。 In addition, the range of content of each component of RO is as follows.
ＭｇＯの含有量は０〜１０％、０．１〜１０％、０．５〜９．５％、１〜９％、特に２〜８％であることが好ましい。 The content of MgO is preferably 0 to 10%, 0.1 to 10%, 0.5 to 9.5%, 1 to 9%, particularly 2 to 8%.
ＣａＯの含有量は０〜１０％、０．１〜１０％、０．５〜９．５％、１〜９％、特に２〜８％であることが好ましい。 The content of CaO is preferably 0 to 10%, 0.1 to 10%, 0.5 to 9.5%, 1 to 9%, particularly 2 to 8%.
ＳｒＯの含有量は、０〜１０％、０．１〜１０％、０．５〜９．５％、１〜９％、特に２〜８％であることが好ましい。 The content of SrO is preferably 0 to 10%, 0.1 to 10%, 0.5 to 9.5%, 1 to 9%, particularly preferably 2 to 8%.
ＢａＯの含有量は、０〜１０％、０．１〜１０％、０．５〜９．５％、１〜９％、特に２〜８％であることが好ましい。 The BaO content is preferably 0 to 10%, 0.1 to 10%, 0.5 to 9.5%, 1 to 9%, particularly 2 to 8%.
ＺｎＯの含有量は、０〜１０％、０．１〜１０％、０．５〜９．５％、１〜９％、特に２〜８％であることが好ましい。 The content of ZnO is preferably 0 to 10%, 0.1 to 10%, 0.5 to 9.5%, 1 to 9%, particularly 2 to 8%.
Ｌｉ２Ｏは、イオン交換成分であり、またガラス転移点を低下させ、さらにガラスの高温粘性を低下させる成分である。Ｌｉ２Ｏの含有量は、０．１〜１０％であり、０．５〜７．５％、１〜７％、特に２〜６％であることが好ましい。Ｌｉ２Ｏの含有量が少なすぎると、イオン交換性能が低下したり、ガラス転移点を低下させることが困難になる。一方、Ｌｉ２Ｏの含有量が多すぎると、紫外線透過率が低下したり、耐候性が悪化しやすくなる。また、プレス成型する際にガラスがプレス金型に融着しやすくなる。 Li 2 O is an ion exchange component, a component that lowers the glass transition point and further lowers the high temperature viscosity of the glass. The content of Li 2 O is 0.1 to 10%, preferably 0.5 to 7.5%, 1 to 7%, particularly 2 to 6%. When the Li 2 O content is too small, the ion exchange performance is lowered, it becomes difficult to lower the glass transition point. On the other hand, when the content of Li 2 O is too large, or reduces the ultraviolet transmittance, weather resistance tends to deteriorate. In addition, the glass is easily fused to the press mold during press molding.
Ｎａ２Ｏ及びＫ２Ｏは、イオン交換成分であり、またガラス転移点を低下させ、さらにガラスの高温粘性を低下させる成分である。Ｎａ２Ｏ＋Ｋ２Ｏの含有量は、３〜２０％であり、４〜１８％、５〜１７％、特に６〜１６％であることが好ましい。Ｎａ２Ｏ＋Ｋ２Ｏの含有量が少なすぎると、イオン交換性能が低下したり、ガラス転移点を低下させることが困難になる。一方、Ｎａ２Ｏ＋Ｋ２Ｏの含有量が多すぎると、紫外線透過率が低下したり、耐候性が悪化しやすくなる。また、プレス成型する際にガラスがプレス金型に融着しやすくなる。 Na 2 O and K 2 O are ion exchange components, and are components that lower the glass transition point and further lower the high temperature viscosity of the glass. The content of Na 2 O + K 2 O is 3 to 20%, preferably 4 to 18%, 5 to 17%, and particularly preferably 6 to 16%. When Na 2 O + K 2 O content is too small, or decreased the ion exchange performance, it is difficult to lower the glass transition point. On the other hand, when the content of Na 2 O + K 2 O is too large, or reduces the ultraviolet transmittance, weather resistance tends to deteriorate. In addition, the glass is easily fused to the press mold during press molding.
なお、Ｎａ２Ｏ及びＫ２Ｏの含有量の好ましい範囲は以下の通りである。 A preferable range of the content of Na 2 O and K 2 O is as follows.
Ｎａ２Ｏは、圧縮応力値を顕著に向上させる成分である。Ｎａ２Ｏの含有量は、１〜２０％、１．５〜１９％、２〜１８％、特に３〜１７％であることが好ましい。 Na 2 O is a component that significantly improves the compressive stress value. The content of Na 2 O is preferably 1 to 20%, 1.5 to 19%, 2 to 18%, particularly 3 to 17%.
Ｋ２Ｏの含有量は、０〜１０％、０．５〜８％、１〜７％、特に２〜６％であることが好ましい。 The content of K 2 O is preferably 0 to 10%, 0.5 to 8%, 1 to 7%, particularly preferably 2 to 6%.
なお、（Ｎａ２Ｏ＋Ｋ２Ｏ）／Ａｌ２Ｏ３は、０．５〜２、０．６〜１．８、０．７〜１．５であることが好ましい。（Ｎａ２Ｏ＋Ｋ２Ｏ）／Ａｌ２Ｏ３が小さすぎると、イオン交換性能が低下したり、ガラス転移点を低下させることが困難になる。一方、（Ｎａ２Ｏ＋Ｋ２Ｏ）／Ａｌ２Ｏ３が大きすぎると、紫外線透過率が低下したり、耐候性が悪化しやすくなる。また、プレス成型する際にガラスがプレス金型に融着しやすくなる。ここで、「（Ｎａ２Ｏ＋Ｋ２Ｏ）／Ａｌ２Ｏ３」とは、Ｎａ２Ｏ及びＫ２Ｏの含有量の合量をＡｌ２Ｏ３の含有量で除した値を指す。 Incidentally, (Na 2 O + K 2 O) / Al 2 O 3 is preferably 0.5～2,0.6～1.8,0.7～1.5. When (Na 2 O + K 2 O) / Al 2 O 3 is too small, it is difficult to lower the ion exchange performance or lower the glass transition point. On the other hand, when (Na 2 O + K 2 O) / Al 2 O 3 is too large, the ultraviolet transmittance is lowered or the weather resistance is liable to be deteriorated. In addition, the glass is easily fused to the press mold during press molding. Here, “(Na 2 O + K 2 O) / Al 2 O 3 ” refers to a value obtained by dividing the total content of Na 2 O and K 2 O by the content of Al 2 O 3 .
ＺｒＯ２は、イオン交換性能を顕著に向上させ、また耐候性を向上させる成分である。ＺｒＯ２の含有量は、０〜３％であり、０〜２％、特に０．１〜２％であることが好ましい。ＺｒＯ２の含有量が多すぎると、紫外線透過率が低下したり、液相粘度が低下し失透しやすくなる。 ZrO 2 is a component that significantly improves the ion exchange performance and also improves the weather resistance. The content of ZrO 2 is 0 to 3%, preferably 0 to 2%, particularly preferably 0.1 to 2%. When the content of ZrO 2 is too large, or reduces the ultraviolet transmittance, the liquid phase viscosity tends to be devitrified reduced.
Ｆ２は紫外線透過率を高める成分である。Ｆ２の含有量は０〜５％であり、０．５〜３％、特に１〜２％であることが好ましい。Ｆ２の含有量が多すぎると、溶融時の蒸発が増加して脈理等が発生し、ガラスが不均質になりやすい。また、プレス成型する際にガラスがプレス金型に融着しやすくなる。さらに、ヤング率が低下したり、圧縮応力値が低下しやすくなる。なお、蒸発等の抑制を優先する場合、Ｆ２は含有しないことが好ましい。 F 2 is a component that increases the ultraviolet transmittance. The content of F 2 is 0 to 5%, preferably 0.5 to 3%, particularly preferably 1 to 2%. When the content of F 2 is too large, evaporation at the time of melting increases, causing striae and the like, and the glass tends to be inhomogeneous. In addition, the glass is easily fused to the press mold during press molding. Furthermore, the Young's modulus decreases and the compressive stress value tends to decrease. In the case where priority is given to suppression of evaporation or the like, it is preferable that F 2 does not contain.
上記成分以外にも、以下に示す種々の成分を含有させることができる。 In addition to the above components, the following various components can be contained.
Ｌａ２Ｏ３、Ｎｂ２Ｏ５、Ｂｉ２Ｏ３及びＷＯ３は耐侯性及び化学耐候性を高める成分である。また、これらの成分を含有させることにより、屈折率を調整することができる。Ｌａ２Ｏ３＋Ｎｂ２Ｏ５＋Ｂｉ２Ｏ３＋ＷＯ３の含有量は０〜０．０５％であることが好ましい。これらの成分の含有量が多すぎると、耐失透性の低下、溶融温度の上昇、あるいは紫外線透過率の低下等の不具合が生じやすくなる。なお、Ｌａ２Ｏ３、Ｎｂ２Ｏ５、Ｂｉ２Ｏ３及びＷＯ３の各成分の含有量も、それぞれ上記範囲であることが好ましい。 La 2 O 3 , Nb 2 O 5 , Bi 2 O 3 and WO 3 are components that enhance weather resistance and chemical weather resistance. Moreover, a refractive index can be adjusted by containing these components. The content of La 2 O 3 + Nb 2 O 5 + Bi 2 O 3 + WO 3 is preferably 0 to 0.05%. When there is too much content of these components, it will become easy to produce malfunctions, such as a fall of devitrification resistance, a raise of melting temperature, or a fall of ultraviolet-ray transmittance. The content of each component of the La 2 O 3, Nb 2 O 5, Bi 2 O 3 and WO 3 is also preferably respectively within the above range.
ＴｉＯ２は紫外線透過率を低下させやすいため、その含有量は極力少ないほうが好ましい。具体的には、ＴｉＯ２の含有量は、１００ｐｐｍ以下、特に５０ｐｐｍ以下であることが好ましい。なお、ＴｉＯ２の含有量の下限値は特に限定されないが現実的には０．１ｐｐｍ以上である。 Since TiO 2 tends to lower the ultraviolet transmittance, its content is preferably as small as possible. Specifically, the content of TiO 2 is preferably 100 ppm or less, particularly 50 ppm or less. The lower limit of the content of TiO 2 is not particularly limited in practice is 0.1ppm or more.
不純物として混入しやすいＦｅ２Ｏ３は紫外線透過率を低下させやすいため、その含有量は極力少ないほうが好ましい。具体的には、Ｆｅ２Ｏ３の含有量は、５０ｐｐｍ以下、特に３０ｐｐｍ以下であることが好ましい。なお、Ｆｅ２Ｏ３の含有量の下限値は特に限定されないが現実的には０．１ｐｐｍ以上である。 Fe 2 O 3 that is likely to be mixed as an impurity is liable to lower the ultraviolet transmittance, and therefore its content is preferably as small as possible. Specifically, the content of Fe 2 O 3 is preferably 50 ppm or less, particularly preferably 30 ppm or less. In addition, the lower limit of the content of Fe 2 O 3 is not particularly limited, but is actually 0.1 ppm or more.
ガラスを溶融する際に還元剤となるカーボンや金属スズ等の成分を１％以下添加しても構わない。 Components such as carbon and metallic tin that are reducing agents when the glass is melted may be added in an amount of 1% or less.
また、Ｃｕ、Ａｇ、Ｐｒ、Ｂｒはガラスを着色させる成分であることから、実質的に含有しないことが好ましい。Ｃｄは環境に対する影響を考慮し、実質的に含有しないことが好ましい。なお、「Ｃｕ、Ａｇ、Ｐｒ、Ｂｒ、Ｃｄを実質的に含有しない」とは、原料として意図的に含有させないことを意味し、客観的には、Ｃｕ、Ａｇ、Ｐｒ、Ｂｒ、Ｃｄの含有量が各々０．０５％未満であることをいう。 Moreover, since Cu, Ag, Pr, and Br are components which color glass, it is preferable that they are not substantially contained. Considering the influence on the environment, Cd is preferably not substantially contained. “Substantially free of Cu, Ag, Pr, Br, Cd” means that it is not intentionally contained as a raw material, and objectively contains Cu, Ag, Pr, Br, Cd. Each amount is less than 0.05%.
以上の組成を有する光学ガラスは、屈折率ｎｄが１．４５〜１．５５、１．４８〜１．５３、特に１．４９〜１．５２になりやすい。また、アッベ数が５０〜６５、５２〜６３、特に５４〜６０になりやすい。 The optical glass having the above composition tends to have a refractive index nd of 1.45 to 1.55, 1.48 to 1.53, particularly 1.49 to 1.52. Further, the Abbe number tends to be 50 to 65, 52 to 63, particularly 54 to 60.
本発明の光学ガラスは、上記のように屈折率が比較的低いため、光入射効率が高い。そのため、表面に反射防止膜を設けなくても実質上問題ない。ただし、必要に応じて、反射防止膜を形成しても構わない。 Since the optical glass of the present invention has a relatively low refractive index as described above, the light incident efficiency is high. Therefore, there is substantially no problem even if an antireflection film is not provided on the surface. However, an antireflection film may be formed as necessary.
本発明の光学ガラスは、ガラス転移点が５５０℃以下、５３０℃以下、特に５００℃以下であることが好ましい。ガラス転移点の下限は特に限定されないが、現実的には４００℃以上である。また、軟化点が７５０℃以下、７３０℃以下、特に７１０℃以下であることが好ましい。軟化点の下限はイオン交換処理に用いる溶液の温度以上であることが好ましい。具体的には、４００℃以上、特に４５０℃以上であることが好ましい。ガラス転移点、軟化点が低いため、プレス成型温度が低くなりプレス金型の劣化を抑制しやすい。 The optical glass of the present invention preferably has a glass transition point of 550 ° C. or lower, 530 ° C. or lower, particularly 500 ° C. or lower. Although the minimum of a glass transition point is not specifically limited, Actually, it is 400 degreeC or more. Moreover, it is preferable that a softening point is 750 degrees C or less, 730 degrees C or less, especially 710 degrees C or less. The lower limit of the softening point is preferably equal to or higher than the temperature of the solution used for the ion exchange treatment. Specifically, it is preferably 400 ° C. or higher, particularly 450 ° C. or higher. Since the glass transition point and the softening point are low, the press molding temperature is lowered and the deterioration of the press mold is easily suppressed.
本発明の光学ガラスは、ガラス転移点と軟化点の差が２４５℃以下、２２０℃以下、特に２００℃以下であることが好ましい。ガラス転移点と軟化点の差が小さいと、プレス成型し冷却する際にガラスが早く固化しやすくなるため、ガラスがプレス金型に融着しにくくなる。 In the optical glass of the present invention, the difference between the glass transition point and the softening point is preferably 245 ° C. or lower, 220 ° C. or lower, particularly 200 ° C. or lower. If the difference between the glass transition point and the softening point is small, the glass tends to solidify quickly when it is press-molded and cooled, so that the glass is difficult to fuse to the press mold.
本発明の光学ガラスは、３０〜３００℃の範囲における熱膨張係数が５０×１０−７／℃以上、６０×１０−７／℃以上、特に７０×１０−７／℃以上であることが好ましい。熱膨張係数が低すぎると、プレス成型し、冷却した後、プレス金型からガラスが離型しにくくなる。なお、熱膨張係数の上限は特に限定されないが、現実的には１５０×１０−７／℃以下である。 The optical glass of the present invention preferably has a thermal expansion coefficient in the range of 30 to 300 ° C. of 50 × 10 −7 / ° C. or higher, 60 × 10 −7 / ° C. or higher, particularly 70 × 10 −7 / ° C. or higher. . If the thermal expansion coefficient is too low, it becomes difficult to release the glass from the press mold after press molding and cooling. The upper limit of the thermal expansion coefficient is not particularly limited, but is practically 150 × 10 −7 / ° C. or less.
本発明の光学ガラスは、概ね波長３５０ｎｍ以下の深紫外域において良好な光透過率を有する。具体的には、本発明の光学ガラスは、肉厚１ｍｍで波長２７０ｎｍにおける光透過率が５０％以上、６０％以上、特に７０％以上であることが好ましい。また、肉厚１ｍｍで波長３００ｎｍにおける光透過率が８０％以上、８５％以上、特に９０％以上であることが好ましい。 The optical glass of the present invention has a good light transmittance in the deep ultraviolet region having a wavelength of approximately 350 nm or less. Specifically, the optical glass of the present invention preferably has a light transmittance of 50% or more, 60% or more, particularly 70% or more at a thickness of 1 mm and a wavelength of 270 nm. Further, the light transmittance at a thickness of 1 mm and a wavelength of 300 nm is preferably 80% or more, 85% or more, particularly 90% or more.
次に、本発明の光学ガラスを製造する方法を述べる。 Next, a method for producing the optical glass of the present invention will be described.
まず、所望の組成になるようにガラス原料を調合した後、ガラス溶融炉で溶融する。ガラスの溶融温度は１１５０℃以上、１２００℃以上、特に１２５０℃以上であることが好ましい。なお溶融容器を構成する白金金属からのＰｔ溶け込みによるガラス着色を防止する観点から、溶融温度は１４５０℃以下、１４００℃以下、１３５０℃以下、特に１３００℃以下であることが好ましい。 First, after preparing a glass raw material so that it may become a desired composition, it fuse | melts with a glass melting furnace. The melting temperature of the glass is preferably 1150 ° C. or higher, 1200 ° C. or higher, particularly 1250 ° C. or higher. Note that the melting temperature is preferably 1450 ° C. or lower, 1400 ° C. or lower, 1350 ° C. or lower, particularly 1300 ° C. or lower from the viewpoint of preventing glass coloring due to Pt melting from platinum metal constituting the melting vessel.
また溶融時間が短すぎると、十分に脱泡できない可能性があるので、溶融時間は２時間以上、特に３時間以上であることが好ましい。ただし溶融容器からのＰｔ溶け込みによるガラス着色を防止する観点から、溶融時間は８時間以内、特に５時間以内であることが好ましい。 Further, if the melting time is too short, there is a possibility that sufficient defoaming cannot be performed. Therefore, the melting time is preferably 2 hours or more, particularly 3 hours or more. However, from the viewpoint of preventing glass coloring due to Pt penetration from the melting vessel, the melting time is preferably within 8 hours, particularly within 5 hours.
次に、溶融ガラスをノズルの先端から滴下して液滴状ガラスを作製し、ガラス母材を得る。または、溶融ガラスを急冷鋳造して一旦ガラスブロックを作製し、研削、研磨、洗浄してガラス母材を得る。 Next, molten glass is dropped from the tip of the nozzle to produce droplet glass, and a glass base material is obtained. Alternatively, a molten glass is rapidly cast to produce a glass block, which is then ground, polished and washed to obtain a glass base material.
続いて、精密加工を施した金型中にガラス母材を投入して軟化状態となるまで加熱しながらプレス成型し、金型の表面形状をガラス母材に転写させる。このようにして、プレス成型ガラスを得ることができる。なお、プレス成型ガラスの形状は、平板形状以外の形状を有し、例えば曲面形状、レンズ形状等が挙げられる。 Subsequently, the glass base material is put into a precision-worked mold and press-molded while being heated until it becomes softened, and the surface shape of the mold is transferred to the glass base material. In this way, press-molded glass can be obtained. The shape of the press-molded glass has a shape other than a flat plate shape, and examples thereof include a curved surface shape and a lens shape.
その後、化学強化法にて、プレス成型ガラスの表面に圧縮応力層を形成し、光学ガラスを得る。なお、化学強化法とは、イオン交換によりガラスの表面にイオン半径の大きいアルカリイオンを導入する方法である。化学強化法で圧縮応力層を形成すれば、ガラスの厚みが薄くても、イオン交換処理を行うことができ、所望の機械的強度を得ることができる。なお、イオン交換処理は、例えば４００〜５５０℃の硝酸カリウム溶液中にプレス成型ガラスを１〜８時間浸漬することで行うことができる。 Thereafter, a compressive stress layer is formed on the surface of the press-molded glass by a chemical strengthening method to obtain an optical glass. The chemical strengthening method is a method of introducing alkali ions having a large ion radius to the surface of the glass by ion exchange. If the compressive stress layer is formed by the chemical strengthening method, the ion exchange treatment can be performed even if the glass is thin, and a desired mechanical strength can be obtained. The ion exchange treatment can be performed, for example, by immersing press-molded glass in a potassium nitrate solution at 400 to 550 ° C. for 1 to 8 hours.
得られた光学ガラスにおいて、圧縮応力層の圧縮応力値は５０〜１０００ＭＰａ、１００〜９００ＭＰａ、３００〜８００ＭＰａ、４５０〜７００ＭＰａ、特に５００〜６００ＭＰａであることが好ましい。圧縮応力層の圧縮応力値が大きくなるにつれて、光学ガラスの機械的強度が高くなる。一方、表面に極端に大きな圧縮応力が形成されると、表面にマイクロクラックが発生したり、内在する引っ張り応力が極端に高くなり、逆に光学ガラスの機械的強度が低下する虞があり、また、光学ガラスの内部と圧縮応力層の屈折率差が大きくなり、色収差のバラツキが生じやすくなる。 In the obtained optical glass, the compressive stress value of the compressive stress layer is preferably 50 to 1000 MPa, 100 to 900 MPa, 300 to 800 MPa, 450 to 700 MPa, particularly 500 to 600 MPa. As the compressive stress value of the compressive stress layer increases, the mechanical strength of the optical glass increases. On the other hand, if an extremely large compressive stress is formed on the surface, microcracks may be generated on the surface, or the inherent tensile stress may be extremely high, and conversely, the mechanical strength of the optical glass may be reduced. The difference in refractive index between the inside of the optical glass and the compressive stress layer increases, and variations in chromatic aberration are likely to occur.
得られた光学ガラスにおいて、圧縮応力層の厚みは１〜１００μｍ、５〜５０μｍ、特に１０〜３０μｍであることが好ましい。圧縮応力層の厚みが大きい程、光学ガラスが破損し難くなる。但し、表面に極端に大きな圧縮応力層の厚みが形成されると、表面にマイクロクラックが発生したり、内在する引っ張り応力が極端に高くなり、逆に光学ガラスの機械的強度が低下する虞があり、また内部と圧縮応力層の屈折率差が大きくなり、色収差のバラツキが生じやすくなる。 In the obtained optical glass, the thickness of the compressive stress layer is preferably 1 to 100 μm, 5 to 50 μm, particularly 10 to 30 μm. The greater the thickness of the compressive stress layer, the more difficult the optical glass is broken. However, if an extremely large compressive stress layer thickness is formed on the surface, microcracks may be generated on the surface, or the inherent tensile stress may be extremely high, and conversely, the mechanical strength of the optical glass may be reduced. In addition, the difference in refractive index between the inside and the compressive stress layer becomes large, and variations in chromatic aberration are likely to occur.
以下、本発明の光学ガラスを実施例に基づいて詳細に説明する。 Hereinafter, the optical glass of this invention is demonstrated in detail based on an Example.
表１及び表２は本発明の実施例（試料Ｎｏ．１〜１４）及び比較例（試料Ｎｏ．１５〜１７）を示している。 Tables 1 and 2 show Examples (Sample Nos. 1 to 14) and Comparative Examples (Sample Nos. 15 to 17) of the present invention.
各試料は、次のようにして作製した。 Each sample was produced as follows.
まず、表１及び２に記載の組成となるように調合したガラス原料を白金ルツボに入れ、１３００℃でそれぞれ２時間溶融した。次に、溶融ガラスをカーボン板上に流し出し、冷却固化した後、アニールを行ってガラスブロックを作製した。その後、研削、研磨、洗浄してガラス母材を得た。このようにして得られたガラス母材について、屈折率、ガラス転移点、軟化点、熱膨張係数及び光透過率を測定した。結果を表１及び２に示す。 First, the glass raw material prepared so that it might become the composition of Table 1 and 2 was put into the platinum crucible, and it melted at 1300 degreeC for 2 hours, respectively. Next, the molten glass was poured onto a carbon plate, cooled and solidified, and then annealed to produce a glass block. Thereafter, grinding, polishing, and washing were performed to obtain a glass base material. The glass base material thus obtained was measured for refractive index, glass transition point, softening point, thermal expansion coefficient and light transmittance. The results are shown in Tables 1 and 2.
次に、精密加工を施した金型中に得られたガラス母材を投入して軟化点で加熱しながら加圧成型し、金型の表面形状をガラス母材に転写し、前面曲率半径 ２０ｍｍ、中心厚み ４ｍｍの平凸レンズを得た。 Next, the glass base material obtained is put into a precision-worked mold and press-molded while heating at the softening point, the surface shape of the mold is transferred to the glass base, and the front curvature radius is 20 mm. A plano-convex lens having a center thickness of 4 mm was obtained.
その後、得られた平凸レンズを４４０℃に保持されたＫＮＯ３槽に８時間浸漬し、イオン交換処理を行い光学ガラスを得た。得られた光学ガラスの圧縮応力層の圧縮応力値及び厚みを測定した。結果を表１及び２に示す。 Thereafter, the obtained plano-convex lens was immersed in a KNO 3 tank maintained at 440 ° C. for 8 hours, and subjected to ion exchange treatment to obtain optical glass. The compression stress value and thickness of the compression stress layer of the obtained optical glass were measured. The results are shown in Tables 1 and 2.
屈折率ｎｄは、屈折率計を用いて、ｄ線（波長：５８７．６ｎｍ）における測定値で示した。 The refractive index nd is indicated by a measured value at the d-line (wavelength: 587.6 nm) using a refractometer.
ガラス転移点は、ディラトメーターを用いて測定した。 The glass transition point was measured using a dilatometer.
軟化点は、ファイバーエロンゲーション法を用いて測定した。 The softening point was measured using a fiber elongation method.
熱膨張係数は、ディラトメーターを用いて、３０〜３００℃の温度範囲における値を測定した。 The thermal expansion coefficient was measured using a dilatometer in a temperature range of 30 to 300 ° C.
光透過率は、分光光度計（島津製作所製ＵＶ−３１００）により測定した。 The light transmittance was measured with a spectrophotometer (UV-3100 manufactured by Shimadzu Corporation).
圧縮応力層の圧縮応力値及び厚みは、表面応力計（株式会社東芝製ＦＳＭ−６０００）を用いて干渉縞の本数とその間隔を観察することで算出した。算出に際し、光学弾性定数を２８［（ｎｍ／ｃｍ）／ＭＰａ］とした。 The compressive stress value and thickness of the compressive stress layer were calculated by observing the number of interference fringes and their intervals using a surface stress meter (FSM-6000 manufactured by Toshiba Corporation). In the calculation, the optical elastic constant was set to 28 [(nm / cm) / MPa].
表１及び２から明らかなように、本発明の実施例であるＮｏ．１〜１４の各試料は、屈折率ｎｄが１．４６〜１．５４、ガラス転移点が４４０〜５０５℃、軟化点が６０１〜７１０℃、光透過率（２７０ｎｍ）が５５〜７８％、光透過率（３００ｎｍ）が８１〜９３％、圧縮応力値が４６１〜５８９ＭＰａ、圧縮応力層の深さが１２〜４５μｍであった。これに対して比較例であるＮｏ．１５の試料は、光透過率（２７０ｎｍ）が４５％、光透過率（３００ｎｍ）が７０％と低かった。Ｎｏ．１６の試料は、ガラス転移点が６３０℃、軟化点が７８５℃と高くプレス成型性に劣ることが分かった。Ｎｏ．１７の試料は、圧縮応力層を有していないため、機械的強度に劣ることが分かった。 As is apparent from Tables 1 and 2, No. 1 as an example of the present invention. Each of the samples 1 to 14 has a refractive index nd of 1.46 to 1.54, a glass transition point of 440 to 505 ° C., a softening point of 601 to 710 ° C., a light transmittance (270 nm) of 55 to 78%, light The transmittance (300 nm) was 81 to 93%, the compressive stress value was 461 to 589 MPa, and the depth of the compressive stress layer was 12 to 45 μm. On the other hand, No. which is a comparative example. Sample 15 had a low light transmittance (270 nm) of 45% and a light transmittance (300 nm) of 70%. No. It was found that the sample No. 16 had a high glass transition point of 630 ° C. and a softening point of 785 ° C. and was inferior in press moldability. No. It was found that sample 17 was inferior in mechanical strength because it did not have a compressive stress layer.
Claims (11)
Mass% selected, SiO 2 40~75%, B 2 O 3 0~30%, Al 2 O 3 3~15%, RO 0.1~10% (R is Mg, Ca, Sr, Ba and Zn A glass base material containing 0.1 to 10% of Li 2 O, 3 to 20% of Na 2 O + K 2 O, 0 to 3% of ZrO 2, and 0 to 5% of F 2. The manufacturing method of the optical glass characterized by including the process of obtaining a press-molded glass, and the process of forming a compressive-stress layer in the surface of the said press-molded glass by the chemical strengthening method.
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| WO2022085403A1 (en) * | 2020-10-19 | 2022-04-28 | 株式会社 オハラ | Optical element having compression stress layer |
| CN114728839A (en) * | 2019-11-11 | 2022-07-08 | 日本电气硝子株式会社 | Method for producing porous glass material |
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