JP2019119646A - Manufacturing method of optical element - Google Patents

Abstract

To provide a manufacturing method of an optical element, having low cost, and having a shortened production time.SOLUTION: A manufacturing method of an optical element includes the first press process for obtaining a planar glass intermediate preform by thinning a glass preform by hot pressing the glass preform comprising Si-La based glass having a softening point≤600°C, Bi-B based glass, P-Nb based glass or Si-B based glass, and the second press process for forming an uneven structure on the surface of the planar glass intermediate preform by hot pressing the planar glass intermediate preform.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of manufacturing an optical element such as a lens array.

  In recent years, with the increase of processing capacity of servers and the like, improvement of the mounting technology of optical circuits, cost reduction of optical elements and optical components, etc., the method of interconnect is shifting from electricity to light. In the optical interconnect, the lens array has a function of focusing the light emitted from the laser on an optical fiber, and focusing the light emitted from the optical fiber on a photodetector such as a photodiode. The lens array is formed by forming one or more lens portions on a substrate. Specifically, one in which a plurality of lens portions are formed on a straight line in a substantially central portion on a rectangular substrate can be mentioned.

  As a manufacturing method of the lens array used for the said application, the manufacturing method which etch-processes with respect to optical glass conventionally is mentioned. However, this manufacturing method has a problem that a plurality of steps are required, the manufacturing time is long, and the cost is very high. Then, the manufacturing method which heat-presses the preform glass which ground and grind | polished the ingot of optical glass is proposed. (For example, refer to patent document 1)

Unexamined-Japanese-Patent No. 2010-53020

  Also in the manufacturing method of Patent Document 1, it is necessary to process the base material to be pressed to the size and shape of the final product. Therefore, there is still a problem that the production time is long and the cost is high.

  The present invention has been made to solve the problems as described above, and an object of the present invention is to provide a method for manufacturing an optical element with reduced manufacturing time and lower cost.

The method of manufacturing an optical element according to the present invention is carried out by heat pressing a glass base material comprising a Si-La glass, a Bi-B glass, a P-Nb glass or a Si-B glass having a softening point of ≦ 600 ° C. A first pressing step of thinning the glass base material to obtain a flat glass intermediate base material, and heat pressing the flat glass intermediate base material to form a concavo-convex structure on the surface of the flat glass intermediate base material It is characterized by including the 2nd press process to form. Note that the "Si-La based glass" means a glass containing SiO ₂ and _La 2 _{O 3} as an essential component. The "Bi-B based glass" means a glass containing _Bi 2 _{O 3} and _B 2 _{O 3} as an essential component. The "P-Nb-based glass" means a glass containing P ₂ O ₅ and Nb ₂ O ₅ as essential components. "Si-B-based glass" means a glass containing SiO ₂ and B ₂ O ₃ as essential components.

  In the method of manufacturing an optical element according to the present invention, since the thickness of the glass base material can be processed to the thickness of the final product in the first pressing step, the grinding step and the polishing step can be omitted. Therefore, the optical element can be manufactured in a short time, easily and at low cost. Although the glass having a softening point of ≦ 600 ° C. tends to have low weatherability and burns easily in the polishing process, the optical element manufacturing method of the present invention can omit the polishing process and therefore burns are less likely to occur.

  The optical element produced according to the present invention is preferably a lens array, a wavelength filter or an antireflective plate.

  The manufacturing method of the optical element of the present invention can omit the grinding process and the polishing process. In addition, since the pressing temperature is low, a lens array having high surface accuracy (for example, few linear grooves due to polishing or the like) can be manufactured easily in a short time and at low cost.

It is a typical sectional view showing the manufacturing process of the optical element of the present invention. (A) It is a top view which shows an example of a lens array. (B) It is a longitudinal cross-sectional view which shows an example of a lens array.

  The method of manufacturing the optical element of the present invention will be described with reference to FIG. First, a glass base material 1 having a softening point of ≦ 600 ° C. is prepared. The glass base material 1 may be produced as follows. A glass raw material prepared to have a desired composition and having a softening point of ≦ 600 ° C. is melted to form a molten glass. Next, molten glass is formed into an ingot to obtain a glass material. Furthermore, the obtained glass material is processed to produce a desired glass base material 1. In addition, the composition of the glass which comprises the glass base material 1 is mentioned later. The softening point of the glass base material 1 is preferably as low as possible, and is preferably 550 ° C. or less, particularly 500 ° C. or less. As described later, in consideration of the heat resistance temperature of the press die, there is a restriction on the heating temperature at the time of pressing. On the other hand, for example, in the first pressing step, it is necessary to sufficiently soften the glass base material 1 so that the glass base material 1 can be thinned to a desired thickness. However, if the softening point of the glass base material 1 is too high, it becomes difficult to sufficiently soften the glass base material within the range not exceeding the heat resistance temperature of the press die. Therefore, the lower the softening point of the glass base material 1, the more advantageous.

  The smaller the difference between the glass transition point and the softening point, the faster the glass base material is solidified after press molding, and the glass base material and the die are less likely to be fused. Specifically, the difference between the glass transition point and the softening point of the glass base material is preferably 245 ° C. or less, 220 ° C. or less, particularly 200 ° C. or less.

  Next, the glass base material 1 is softened and deformed sufficiently by heat-pressing the glass base material 1 having a softening point of ≦ 600 ° C. at low temperature using flat plate-like upper and lower molds 2 and thinner than the glass base material 1 A flat glass intermediate base material 3 is obtained. (First pressing step) Here, when the pressing temperature is less than the softening point + 30 ° C., the glass base material 1 is not sufficiently softened and deformed. Further, since the heat resistance temperature of the mold is usually 630 ° C. or less, the softening point of the glass base material 1 needs to be 600 ° C. or less. That is, when the glass base material 1 having a softening point> 600 ° C. is used, in the process of obtaining the flat glass intermediate base material 3, there is a problem such as insufficient softening deformation or high press temperature and breakage of the mold. Occur. In addition, it is preferable that the press temperature in a 1st press process is softening point +30 degreeC or more, especially softening point +40 degreeC or more. The upper limit of the press temperature is not particularly limited, but is preferably the softening point + 100 ° C. or less.

  Next, the plate-like glass intermediate base material 3 is heat-pressed at a low temperature using the plate-like lower die 4 b and the upper die 4 a for forming the concavo-convex structure, whereby the concavo-convex structure is formed on the surface of the glass plate The optical element 5 can be obtained. (Second pressing step) The uneven structure is a structure including a plurality of protrusions, and the shape of the protrusions is not particularly limited. In addition, it is preferable that the press temperature in a 2nd press process is softening point +30 degreeC or more, especially softening point +40 degreeC or more. The upper limit of the press temperature is not particularly limited, but is preferably the softening point + 100 ° C. or less.

  The glass base material is Si-La based glass, Bi-B based glass, P-Nb based glass or Si-B based glass. Si-La based glass, Bi-B based glass, P-Nb based glass and Si-B based glass are suitable as a glass base material in the present invention because they can easily achieve a low softening point.

The Si-La based glass, in _{mass%, SiO 2 1~30%, La} 2 O 3 1~30%, B 2 O 3 1~30%, Al 2 O 3 0~10%, ZnO 1~20 %, CaO 0 to 20%, Li ₂ O 0.1 to 20%, TiO _{2 0 to} 15%, Nb ₂ O ₅ 1 to 30%, ZrO ₂ 0 to 10%, WO ₃ 0 to 15% Is preferred. Below, the reason which specified content of each component as mentioned above is explained in full detail. In addition, unless there is particular notice, the following "%" means "mass%."

SiO ₂ has the effect of increasing liquidus viscosity and improving weatherability. The content of SiO ₂ is preferably 1 to 30%, 1 to 27%, 2 to 24%, particularly 3 to 21%. When the content of SiO ₂ is too small, the above-described effect is hardly obtained. If the content of SiO ₂ is too large, the solubility of the glass may be deteriorated, or the devitrified substance containing SiO ₂ may be easily precipitated.

La ₂ O ₃ has the effect of increasing the refractive index and improving the weather resistance. The content of La ₂ O ₃ is preferably 1 to 30%, 2 to 28%, particularly 5 to 25%. When the content of La ₂ O ₃ is too small, the above-mentioned effects become difficult to obtain. On the other hand, when the content of La ₂ O ₃ is too large, the glass is colored to lower the transmittance, and the liquidus viscosity tends to decrease.

B ₂ O ₃ has the effect of increasing the liquidus viscosity, improving the weatherability, and reducing the high temperature viscosity of the glass. The content of B ₂ O ₃ is preferably 1 to 30%, 4 to 28%, 8 to 26%, particularly 12 to 24%. When the content of B ₂ O ₃ is too small, the above-described effect is hardly obtained. On the other hand, when the content of B ₂ O ₃ is too large, the weather resistance is deteriorated, or evaporation occurs at the time of molding, and striae tends to occur.

Al ₂ O ₃ has the effect of increasing liquidus viscosity and improving weatherability. The content of Al ₂ O ₃ is preferably 0 to 10%, 0 to 7%, 1 to 4%, particularly 1 to 3%. If the content of Al ₂ O ₃ is too large, the solubility of the glass may be deteriorated, or a devitrified material containing Al ₂ O ₃ may be easily precipitated.

  ZnO has the effect of lowering the high temperature viscosity of the glass and lowering the softening point while maintaining the weather resistance. The content of ZnO is preferably 1 to 20%, 3 to 18%, 5 to 16%, particularly 7 to 14%. When the content of ZnO is too small, the above-described effect is hardly obtained. On the other hand, when the content of ZnO is too large, the weather resistance is apt to be deteriorated, and the glass is easily fused to the mold during press molding.

  CaO has the effect of lowering the high temperature viscosity of the glass and lowering the softening point while maintaining the weather resistance. The content of CaO is preferably 0 to 20%, 1 to 18%, 3 to 16%, particularly 5 to 14%. When the content of CaO is too small, the above-mentioned effect is hardly obtained. When the content of CaO is too large, the weather resistance is apt to be deteriorated, the devitrified substance containing CaO is easily precipitated, and the glass is easily fused to the mold during press molding.

Li ₂ O has the effect of reducing the high temperature viscosity of the glass and significantly reducing the softening point. The content of Li ₂ O is preferably 0.1 to 20%, 0.5 to 18%, 1 to 16%, 2 to 14%, particularly 2.5 to 12%. When the content of Li ₂ O is too small, the above-described effects are hardly obtained. On the other hand, when the content of Li ₂ O is too large, the weather resistance tends to deteriorate and the liquid phase viscosity tends to decrease.

TiO ₂ has the effect of increasing the refractive index and improving the weather resistance. The content of TiO ₂ is preferably 0 to 15%, 1 to 15%, 2 to 13%, 3 to 11%, 4 to 9%, particularly 5 to 8%. When the content of TiO ₂ is too small, the above-mentioned effect is hardly obtained. On the other hand, when the content of TiO ₂ is too large, the glass is colored to lower the transmittance, and the liquid phase viscosity tends to decrease.

Nb ₂ O ₅ has the effect of increasing the refractive index and improving the weather resistance. The content of Nb ₂ O ₅ is preferably 1 to 30%, 2 to 27%, 3 to 24%, 4 to 21%, particularly 5 to 18%. When the content of Nb ₂ O ₅ is too small, the above-described effect is hardly obtained. On the other hand, when the content of Nb ₂ O ₅ is too large, the glass is colored to lower the transmittance, and the liquidus viscosity tends to decrease.

ZrO ₂ has the effect of increasing the refractive index and improving the weather resistance. The content of ZrO ₂ is preferably 0 to 10%, 0 to 7%, particularly 0.1 to 4%. When the content of ZrO ₂ is too large, the glass is colored to lower the transmittance, and the liquid phase viscosity tends to decrease.

WO ₃ has the effect of increasing the refractive index and improving the weather resistance. The content of WO ₃ is preferably 0 to 15%, 0 to 10%, particularly 1 to 5%. When the content of WO ₃ is too large, the glass is colored to decrease the transmittance, and the liquid phase viscosity is likely to decrease.

The Bi-B-based glass preferably contains, by mass%, 20 to 90% of Bi ₂ O ₃ , 10 to 30% of B ₂ O ₃ , and 0 to 5.5% of GeO ₂ . Below, the reason which specified content of each component as mentioned above is demonstrated. In addition, unless there is particular notice, "%" means "mass%" in the description regarding the following component content.

Bi ₂ O ₃ has the effect of increasing the refractive index and significantly reducing the softening point. The content of Bi ₂ O ₃ is preferably 20 to 90%, 20 to 85%, 25 to 80%, and particularly 30% to 75%. When the content of Bi ₂ O ₃ is too small, the above-described effect is difficult to be obtained. On the other hand, if the content of Bi ₂ O ₃ is too large, it tends to be difficult to vitrify and the devitrification resistance tends to decrease.

B ₂ O ₃ has the effect of increasing the light transmittance. In particular, in the case of a high refractive index glass, the effect of improving the light transmittance by B ₂ O ₃ is easily obtained. It also has the effect of suppressing devitrification. The content of B ₂ O ₃ is preferably 10% or more, 12% or more, and particularly 14% or more. When the content of B ₂ O ₃ is too small, the above-described effect is hardly obtained. On the other hand, the upper limit of the content of B ₂ O ₃ is not particularly limited, but when the content of B ₂ O ₃ is too large, the content of Bi ₂ O ₃ becomes relatively small, and the refractive index tends to decrease. Or chemical durability is likely to decrease. Therefore, the content of B ₂ O ₃ is preferably 30% or less, particularly 28% or less.

GeO ₂ is a component for obtaining optical properties of high refractive index and high dispersion. However, when it is added in a large amount, the transmittance tends to decrease. In addition, since GeO ₂ is an expensive raw material, if it is used in a large amount, the glass cost becomes high. Accordingly, the content of GeO ₂ is preferably 0 to 5.5%, 0 to 5%, 0 to 4.5%, particularly 0.1 to 4.5%.

In addition to the above components, the Bi-B system glass contains SiO ₂ 0-20%, MgO + CaO + SrO + BaO + ZnO 0-40%, Al ₂ O ₃ 0-10%, ZrO ₂ 0-10%, La ₂ O ₃ + Gd ₂ O ₃ + Ta ₂ O ₅ + Nb ₂ O ₅ + WO ₃ + TiO ₂ 0 to 40% can be contained.

The P-Nb-based glass, in terms of _{mass%, P 2 O 5 25~40%} , Nb 2 O 5 10~30%, SiO 2 0~4%, B 2 O 3 0~4%, Al 2 O 3 0 to 4%, ZnO 0 to 11%, Li ₂ O 1.5 to 6%, Na ₂ O 1 to 20%, K ₂ O 0 to 7%, TiO ₂ 1 to 11%, Bi ₂ O _{30 to} Those containing 15% and WO ₃ 0-10% are preferred. Below, the reason which specified content of each component as mentioned above is explained in full detail. In addition, unless there is particular notice, the following "%" means "mass%."

P ₂ O ₅ has an effect of improving the devitrification resistance to increase the liquidus viscosity, reducing the high temperature viscosity of the glass, and further reducing the softening point. The content of P ₂ O ₅ is preferably 25 to 40%, 26 to 38%, 27 to 36%, particularly 28 to 34%. When the content of P ₂ O ₅ is too small, the above-mentioned effects become difficult to obtain. On the other hand, when the content of P ₂ O ₅ is too large, the weather resistance is apt to deteriorate, and the glass is easily fused to the mold when press-molding.

Nb ₂ O ₅ has the effect of increasing the refractive index and improving the weather resistance. The content of Nb ₂ O ₅ is preferably 10 to 30%, 12 to 28%, 14 to 26%, 16 to 24%, and particularly preferably 18 to 22%. When the content of Nb ₂ O ₅ is too small, the above-described effect is hardly obtained. On the other hand, when the content of Nb ₂ O ₅ is too large, the glass is colored to lower the transmittance, or the devitrification resistance is deteriorated, and the liquidus viscosity tends to be reduced.

SiO ₂ has the effect of improving the weather resistance. The content of SiO ₂ is preferably 0 to 4%, 0 to 3%, particularly 0.1 to 2%. When the content of SiO ₂ is too large, the devitrification resistance is deteriorated and the liquid phase viscosity is easily reduced, and the refractive index is easily reduced, and furthermore, the solubility of the glass is easily deteriorated.

B ₂ O ₃ has the effect of improving the weather resistance. The content of B ₂ O ₃ is preferably 0 to 4%, 0 to 3%, particularly 0.1 to 2%. When the content of B ₂ O ₃ is too large, the devitrification resistance is deteriorated, the liquid phase viscosity is easily reduced, the refractive index is easily reduced, and the solubility of the glass is further deteriorated.

Al ₂ O ₃ has the effect of improving the weather resistance. The content of Al ₂ O ₃ is preferably 0 to 4%, 0 to 3%, particularly 0.1 to 2%. When the content of Al ₂ O ₃ is too large, the devitrification resistance is deteriorated, the liquid phase viscosity is easily reduced, the refractive index is easily reduced, and the solubility of the glass is further deteriorated.

  ZnO has the effect of lowering the high temperature viscosity of the glass and lowering the softening point while maintaining the weather resistance. The content of ZnO is preferably 0 to 11%, 1 to 8%, particularly 2 to 5%. When the content of ZnO is too large, the weather resistance is apt to deteriorate, and the glass is easily fused to the mold during press molding.

Li ₂ O has the effect of reducing the high temperature viscosity of the glass and significantly reducing the softening point. The content of Li ₂ O is preferably 1.5 to 6%, 2 to 5%, particularly 2 to 4%. When the content of Li ₂ O is too small, the above-described effects are hardly obtained. On the other hand, when the content of Li ₂ O is too large, the weather resistance tends to deteriorate, and the devitrification resistance deteriorates and the liquid phase viscosity tends to decrease.

Na ₂ O has the effect of lowering the high temperature viscosity of the glass and significantly reducing the softening point. The content of Na ₂ O is preferably 1 to 20%, 3 to 18%, 5 to 16%, particularly 7 to 14%. When the content of Na ₂ O is too small, the above-described effect is hardly obtained. On the other hand, when the content of Na ₂ O is too large, the weather resistance tends to be deteriorated, and the devitrification resistance is deteriorated, so that the liquid phase viscosity tends to be lowered.

K ₂ O has the effect of lowering the high temperature viscosity of the glass and lowering the softening point. The content of K ₂ O is preferably 0 to 7%, 0 to 6%, 0 to 5%, particularly 0.1 to 4%. If the content of K ₂ O is too large, the weather resistance tends to deteriorate, and the devitrification resistance deteriorates, and the liquidus viscosity tends to decrease.

TiO ₂ has the effect of increasing the refractive index and improving the weather resistance. The content of TiO ₂ is preferably 1 to 11%, 2 to 10%, particularly 3 to 9%. When the content of TiO ₂ is too small, the above-mentioned effect is hardly obtained. On the other hand, when the content of TiO ₂ is too large, the glass is colored to lower the transmittance, or the devitrification resistance is deteriorated, and the liquid phase viscosity tends to be reduced.

Bi ₂ O ₃ has the effect of increasing the refractive index and significantly reducing the softening point. The content of Bi ₂ O ₃ is preferably 0 to 15%, 0 to 12%, particularly 1 to 9%. When the content of Bi ₂ O ₃ is too large, the glass is colored to reduce the transmittance, and the glass is easily fused to the press die.

WO ₃ has the effect of increasing the refractive index and improving the weather resistance. The content of WO ₃ is preferably 0 to 10%, 3 to 9%, particularly 6 to 9%. When the content of WO ₃ is too large, the glass is colored to lower the transmittance, or the devitrification resistance is deteriorated, and the liquidus viscosity tends to be reduced.

  In addition to the above components, the P-Nb-based glass can contain various components described below.

  MgO, CaO, SrO and BaO have the effect of lowering the high temperature viscosity of the glass and lowering the softening point while maintaining the weather resistance. The content of MgO + CaO + SrO + BaO is preferably 0 to 2%, and more preferably 0.1 to 1%. When the content of MgO + CaO + SrO + BaO is too large, the devitrification resistance is deteriorated, the liquid phase viscosity is easily lowered, and the weather resistance is easily deteriorated, and furthermore, the glass is easily fused to the mold when press-molding. Here, “MgO + CaO + SrO + BaO” means the total content of MgO, CaO, SrO and BaO.

  In addition, the preferable range of content of MgO, CaO, SrO, and BaO is as follows.

  The content of MgO is preferably 0 to 2%, particularly 0 to 1%.

  The content of CaO is preferably 0 to 2%, particularly 0.1 to 1%.

  The content of SrO is preferably 0 to 2%, particularly 0 to 1%.

  The content of BaO is preferably 0 to 2%, particularly 0 to 1%.

ZrO ₂ has the effect of increasing the refractive index and improving the weather resistance. The content of ZrO ₂ is preferably 0 to 5%, 0 to 3%, particularly 0 to 1%. When the content of ZrO ₂ is too large, the glass is colored to lower the transmittance, or the devitrification resistance is deteriorated, and the liquid phase viscosity is easily reduced.

La ₂ O ₃ has the effect of increasing the refractive index and improving the weather resistance. The content of La ₂ O ₃ is preferably 0 to 5%, 0 to 3%, particularly 0.1 to 1%. When the content of La ₂ O ₃ is too large, the glass is colored to lower the transmittance, or the devitrification resistance is deteriorated, and the liquid phase viscosity tends to be reduced.

The Si-B-based glass, in _{mass%, SiO 2 10~70%, B} 2 O 3 1~60%, Al 2 O 3 0~30%, MgO + CaO + SrO + BaO + 0~50% ZnO, Li 2 O + Na 2 O + K 2 O Those containing 0.1 to 30% are preferred. Below, the reason which specified content of each component as mentioned above is demonstrated. In addition, unless there is particular notice, "%" means "mass%" in the description regarding the following component content. Here, “MgO + CaO + SrO + BaO + ZnO” means the total content of MgO, CaO, SrO, BaO and ZnO. “Li ₂ O + Na ₂ O + K ₂ O” means the total content of Li ₂ O, Na ₂ O and K ₂ O.

SiO ₂ has the effect of improving the weather resistance. The content of SiO ₂ is preferably 10 to 70%, 20 to 62%, 30 to 60%, particularly 40 to 60%. When the content of SiO ₂ is too small, the above-described effect is hardly obtained. On the other hand, when the content of SiO ₂ is too large, the high temperature viscosity becomes high. In addition, the refractive index is low, and the softening point tends to be high.

B ₂ O ₃ has the effect of lowering the high temperature viscosity of the glass. The content of B ₂ O ₃ is preferably 1 to 60%, 5 to 40%, 10 to 30%, particularly 15 to 25%. When the content of B ₂ O ₃ is too small, the above-described effect is hardly obtained. On the other hand, when the content of B ₂ O ₃ is too large, the weather resistance tends to be lowered.

Al ₂ O ₃ has the effect of improving the weather resistance. The content of Al ₂ O ₃ is preferably 0 to 30%, 5 to 25%, particularly 10 to 20%. When the content of Al ₂ O ₃ is too large, the high temperature viscosity of the glass becomes high. In addition, the refractive index tends to decrease and the softening point tends to increase.

  MgO, CaO, SrO, BaO and ZnO are effective in lowering the high temperature viscosity of the glass. It is also a component that enhances the weather resistance. The total amount of these is preferably 0 to 50%, 5 to 45%, 10 to 40%, and particularly preferably 15 to 35%. If the total amount of these components is too large, devitrification tends to occur during molding.

  MgO can be added up to 30% to improve the weather resistance and to increase the refractive index. The content of MgO is preferably 30% or less, 20% or less, and particularly 10% or less. When the content of MgO is too high, the tendency to separate is strong and the liquidus temperature tends to be increased.

  CaO has the effect of lowering the softening point. It also has the effect of increasing the refractive index. The content of CaO is preferably 0 to 40%, particularly 1 to 30%. If the content of CaO is too large, the weather resistance tends to deteriorate.

  SrO has an effect of improving the weather resistance and the refractive index. The content of SrO is preferably 0 to 40%, particularly 1 to 30%. If the content of SrO is too large, the weather resistance tends to deteriorate.

  BaO is a component that enhances the weather resistance and enhances the refractive index, and is a component that reduces the liquidus temperature of the glass to improve the workability. The content of BaO is preferably 0 to 40%, particularly 1 to 30%. If the content of BaO is too large, the weather resistance tends to deteriorate.

  ZnO is a component to be added to enhance the refractive index and to improve the weather resistance, and can be contained up to 30%. However, when the content of ZnO is too large, the devitrification tendency becomes strong, and it becomes difficult to obtain a homogeneous glass, so the content is preferably 20% or less.

Li ₂ O, Na ₂ O and K ₂ O have the effect of lowering the melting temperature and the softening point. The total amount of these is preferably 0.1 to 30%, 1 to 18%, particularly 8 to 18%. When the total amount of these components is too small, the above-mentioned effect becomes difficult to be obtained. On the other hand, if the total amount of these is too large, the weather resistance tends to deteriorate.

Li ₂ O has the effect of lowering the high temperature viscosity and softening point of glass. The content of Li ₂ O is preferably 0 to 12%, particularly 0.1 to 10%. When the content of Li ₂ O is too large, the liquidus temperature becomes high and the workability becomes worse.

Na ₂ O has the effect of lowering the high temperature viscosity and softening point of glass. The content of Na ₂ O is preferably 0 to 12%, particularly 0.1 to 10%. When the content of Na ₂ O is too large, volatiles formed of B ₂ O ₃ -Na ₂ O at the time of melting the glass tend to promote formation of striae.

K ₂ O has the effect of lowering the high temperature viscosity and softening point of glass. The content of K ₂ O is preferably 12% or less, particularly 10% or less. When the content of K ₂ O is too large, volatiles formed of B ₂ O ₃ -K ₂ O at the time of glass melting tend to be increased to promote the formation of cord.

  In addition to the above components, various components shown below can be contained.

ZrO ₂ is a component added to improve the weather resistance as well as to increase the refractive index. However, when the content of ZrO ₂ is too large, the devitrification tendency becomes strong and a homogeneous glass can not be obtained, so the content is preferably 3% or less, particularly less than 0.1%.

La ₂ O ₃ has the effect of increasing the refractive index. However, if the content of La ₂ O ₃ is too large, it tends to be devitrified, so the content is preferably 2.5% or less, particularly less than 1%.

Bi ₂ O ₃ is a component added to increase the refractive index. However, if the content of Bi ₂ O ₃ is too large, the glass tends to be colored, so the content is preferably 5% or less, particularly 0.1%.

P ₂ O ₅ is a component added to lower the liquidus temperature. However, when the content of P ₂ O ₅ is too large, the glass tends to be separated easily, so the content is preferably 5% or less, particularly less than 0.1%.

As an optical element manufactured by the method of this invention, a lens array, a wavelength filter, a reflection preventing plate etc. are mentioned. The lens array will be described below. FIG. 2 shows an embodiment of a lens array manufactured by the manufacturing method of the present invention. As shown in FIG. 2, the lens array 6 is formed by forming a plurality of lens portions 8 on, for example, a straight line on a glass substrate 7.
The radius of curvature (central radius of curvature) of the lens portion in the lens array is preferably 0.10 mm or more, more preferably 0.15 mm or more, still more preferably 0.18 mm or more, still more preferably 0.20 mm or more, still more preferably 0 It is .25 mm or more. If the curvature radius of the lens portion is too small, insufficient glass filling easily occurs in the mold recess during heat pressing, and it is difficult to obtain a lens array having a desired size. In addition, due to the difference in thermal expansion between the mold and the glass, distortion occurs in the lens portion, and cracking is likely to occur. The upper limit of the radius of curvature of the lens portion is not particularly limited, but if it is too large, the lens does not function as a lens (does not have a light collecting function), so it is 1 mm or less, and further 0.5 mm or less Is preferred.

  The diameter of the lens portion is preferably 0.05 to 0.5 mm, more preferably 0.1 to 0.4 mm, and still more preferably 0.2 to 0.3 mm. If the diameter of the lens portion is too small, all the light emitted from the laser or the optical fiber will not be incident on the lens portion, resulting in a loss of light or the incident light tends to affect surrounding optical systems as vignetting. is there. On the other hand, when the diameter of the lens portion is too large, it becomes difficult to form a large number of lens portions on a minute glass substrate.

  The optical element produced according to the present invention preferably has a transmittance at a wavelength of 380 to 1600 nm (particularly, a lens portion) of 70% or more, more preferably 80% or more, still more preferably 90% or more, particularly preferably 95% or more , Most preferably 99% or more. If the transmittance at a wavelength of 380 to 1600 nm is less than 70%, the loss due to light scattering or absorption tends to be large, and the light collection efficiency tends to be inferior.

  Moreover, when adhering the optical element manufactured by this invention to photodetectors, such as a photodiode, using an ultraviolet curable resin, ultraviolet light is irradiated to ultraviolet curable resin through an optical element. Therefore, the higher the transmittance in the ultraviolet region of the optical element, the larger the light irradiation amount to the ultraviolet curing resin, which is preferable because curing becomes easy. Specifically, in the optical element of the present invention, the transmittance at a wavelength of 330 to 380 nm is preferably 70% or more, more preferably 80% or more, still more preferably 90% or more, particularly preferably 95% or more, most preferably Is over 99%.

  In addition, "the transmittance | permeability" here means the spectral transmission factor which does not contain reflection, and means the ratio of the transmitted light with respect to the incident light at the time of injecting a light ray into an optical element.

  The optical element manufactured according to the present invention may have linear protrusions formed on the surface. This is considered to be the result of polishing scratches and the like formed on the surface of the mold being transferred to the surface of the glass at the time of heat pressing, which can be said to be a feature of the optical element manufactured by the heat pressing.

  Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited to these examples.

Example 1
% By mass, SiO ₂ 13.9%, B ₂ O ₃ 18%, ZnO 10%, CaO 19%, Li ₂ O 9%, TiO ₂ 5%, Nb ₂ O ₅ 9%, ZrO ₂ 5%, La ₂ O _{3 11%,} to prepare a raw material so as to _Sb 2 O 3 0.1%, was melted for 1 hour at 1300 ° C.. On a preheated metal plate, molten glass was poured out, annealed, and processed to prepare a 3 mm × 3 mm × 3 mm glass base material.

  When each characteristic was measured about the obtained glass base material, refractive index (nd) was 1.727 and the softening point was 490 degreeC. In addition, the refractive index was shown by the measured value with respect to d line (587.6 nm) of a helium lamp. Moreover, the softening point was made into the softening point the value of the 4th inflexion point in the chart obtained by measuring to 1000 degreeC using a macro-type differential thermal analyzer.

  The glass base material obtained above was pressed at 520 ° C. and 100 kPa in a nitrogen atmosphere using flat plate-like upper and lower molds to obtain a flat plate-like intermediate base material having a thickness of 2.5 mm. Furthermore, by pressing the intermediate base material at 530 ° C. using a flat lower mold and an upper mold for forming a lens array, 12 lens portions are straight on the approximate center of the rectangular substrate. The optical elements arranged in

  The shape and dimensions of the produced optical element were as follows.

Board dimensions: 2.5 x 3.3 x 0.5 mm
Lens part (average value): curvature radius 0.201 mm, diameter 0.227 mm
0.035 mm in height

(Example 2)
By _{mass%, Bi 2 O 3 80.2%} , B 2 O 3 17.7%, WO 3 2%, to prepare a raw material so as to _Sb 2 O 3 0.1%, 1 hour melted at 950 ° C. did. On a preheated metal plate, molten glass was poured out, annealed, and processed to prepare a 3 mm × 3 mm × 3 mm glass base material.

  When each characteristic was measured about the obtained glass base material, refractive index (nd) was 2.011 and the softening point was 450 degreeC.

  The glass base material obtained above was pressed at 480 ° C. and 100 kPa in a nitrogen atmosphere using flat plate-like upper and lower molds to obtain a flat plate-like intermediate base material having a thickness of 2.5 mm. Furthermore, by pressing the intermediate base material at 510 ° C. using a flat lower mold and an upper mold for forming a lens array, 12 lens portions are straight on the approximate center of the rectangular substrate. The optical elements arranged in

  The shape and dimensions of the produced optical element were as follows.

Board dimensions: 2.5 x 3.3 x 0.5 mm
Lens part (average value): radius of curvature 0.205 mm, diameter 0.229 mm
0.034 mm in height

(Example 3)
P ₂ O ₅ 29.9%, Nb ₂ O ₅ 21%, B ₂ O ₃ 1%, ZnO 5%, Li ₂ O 3%, Na ₂ O 13%, K ₂ O 3%, TiO _{2 by} mass% _The raw materials were formulated to be 28%, WO ₃ 9%, Bi ₂ O ₃ 7%, Sb ₂ O ₃ 0.1%, and melted at 1300 ° C. for 1 hour. On a preheated metal plate, molten glass was poured out, annealed, and processed to prepare a 3 mm × 3 mm × 3 mm glass base material.

  When each characteristic was measured about the obtained glass base material, refractive index (nd) was 1.717 and the softening point was 480 degreeC.

  The glass base material obtained above was pressed at 510 ° C. and 100 kPa using flat plate-like upper and lower molds to obtain a flat plate-like intermediate base material having a thickness of 2.5 mm. Furthermore, by pressing the intermediate base material at 520 ° C. using a flat lower mold and an upper mold for forming a lens array, 12 lens portions are straight on the approximate center of the rectangular substrate. The optical elements arranged in

  The shape and dimensions of the produced optical element were as follows.

Board dimensions: 2.5 x 3.3 x 0.5 mm
Lens part (average value): radius of curvature 0.200 mm, diameter 0.223 mm
0.034 mm in height

(Example 4)
The raw materials are prepared so that the mass ratio becomes 52.9% of SiO ₂ , 19% of B ₂ O ₃ , 15% of Al ₂ O ₃ , 13% of Na ₂ O, 0.1% of Sb ₂ O ₃ , 1250 ° C. Melted for 1 hour. On a preheated metal plate, molten glass was poured out, annealed, and processed to prepare a 3 mm × 3 mm × 3 mm glass base material.

  When each characteristic was measured about the obtained glass base material, refractive index (nd) was 1.507 and the softening point was 480 degreeC.

  The glass base material obtained above was pressed at 510 ° C. and 100 kPa using flat plate-like upper and lower molds to obtain a flat plate-like intermediate base material having a thickness of 2.5 mm. Furthermore, by pressing the intermediate base material at 520 ° C. using a flat lower mold and an upper mold for forming a lens array, 12 lens portions are straight on the approximate center of the rectangular substrate. The optical elements arranged in

  The shape and dimensions of the produced optical element were as follows.

Board dimensions: 2.5 x 3.3 x 0.5 mm
Lens part (average value): radius of curvature 0.205 mm, diameter 0.225 mm
0.035 mm in height

(Comparative example)
% By mass, B ₂ O ₃ 21%, La ₂ O ₃ 25%, ZnO 20%, Gd ₂ O ₃ 10%, SiO ₂ 5%, Ta ₂ O ₅ 7%, ZrO ₂ 5%, WO ₃ 2% The raw materials were prepared to have 5% Nb ₂ O _{5 and} melted at 1300 ° C. for 2 hours. On a preheated metal plate, molten glass was poured out, annealed, and processed to prepare a 3 mm × 3 mm × 3 mm glass base material.

  When each characteristic was measured about the obtained glass base material similarly to the above, it was refractive index (nd) 1.805 and softening point 620 degreeC.

  The glass base material obtained above was pressed at 630 ° C. and 100 kPa in a vacuum atmosphere using flat plate-like upper and lower molds, but an intermediate base material having a desired thickness was obtained without sufficient softening deformation. It was not. In addition, when the press pressure was raised to 200 kPa, the glass base material was damaged.

  The method of the present invention is suitable as a manufacturing method of a lens array, a wavelength filter or an antireflective plate, but is not limited thereto.

DESCRIPTION OF SYMBOLS 1 glass base material 2 mold 2a upper mold 2b lower mold 3 middle base material 4 mold 4a upper mold 4b lower mold 5 optical element 6 lens array 7 glass substrate 8 lens part D lens part diameter H lens part Height of

Claims (2)

  Heat-pressing a glass base material consisting of a Si-La glass, Bi-B glass, P-Nb glass or Si-B glass having a softening point ≦ 600 ° C. to thin the glass base material and form a flat plate Including a first pressing step of obtaining a glass intermediate base material, and a second pressing step of forming a concavo-convex structure on the surface of the flat glass intermediate base material by heat-pressing the flat glass intermediate base material A manufacturing method of an optical element characterized by the above.   The method of manufacturing an optical element according to claim 1, wherein the optical element is a lens array, a wavelength filter, or an antireflective plate.