JP4605543B2 - Optical glass package - Google Patents

Description

  The present invention relates to an optical glass package that is unlikely to deteriorate in quality even when optical glass is stored for a long period of time.

  Optical glass is used for a pickup lens of an optical disc system such as a CD, MD, and DVD, and a photographing lens of a video camera or a general camera. There are cases where the optical glass is directly melted and molded by an optical component manufacturer, and cases where the optical glass is melted and pre-molded by a glass manufacturer and then formed by an optical component manufacturer.

In the former case, there is almost no problem, but in the latter case, since it takes time from pre-molding to main molding, foreign matter such as dust may be attached to the surface of the optical glass. When processed into a defect. Therefore, the pre-molded optical glass is filled in a bag-shaped plastic container, packed in a sealed state, and stored or transported (for example, see Patent Document 1).
JP 2004-59154 A

  By the way, when the optical glass is stored or transported for a long period of time, the surface of the optical glass may become cloudy. Since optical glass has very strict requirements on surface quality, there are cases where optical glass having a cloudy surface as described above cannot be used.

  An object of the present invention is to provide an optical glass package that hardly causes fogging on the surface of the optical glass even when the optical glass is stored or transported for a long period of time.

  As a result of intensive studies, the present inventors have found that the main factor that cloudes the surface of the optical glass is moisture in the air, and by using a container with low moisture permeability (moisture permeability) instead of a plastic container. It is ascertained that the fogging generated on the surface of the optical glass can be suppressed, and is proposed as the present invention.

That is, in the optical glass package of the present invention, the optical glass is placed on a tray with a partition to avoid contact between the optical glasses, and only the optical glass and the tray are placed in a bag-like container. In the optical glass package formed by sealing, the container is made of a resin laminate containing any one of a metal thin film, an inorganic oxide thin film, and an inorganic nitride thin film, and the container measured by the method described in JIS Z 0222 The moisture permeability is 10 g / m ² · 24 h or less , and the CO ₂ permeability measured by the method described in JIS K 7126 is 10 cc / m ² · 24 h · atm or less .

  In the optical glass package of the present invention, the optical glass is tightly packaged using a bag-like container having low moisture permeability. Is difficult to penetrate. Therefore, even if the optical glass has poor weather resistance, it is possible to suppress the occurrence of fogging on the optical glass surface during long-term storage or transportation.

The optical glass package of the present invention uses a container having a moisture permeability of 10 g / m ² · 24 h or less measured by the method of JIS Z 0222. If the moisture permeability is greater than 10 g / m ² · 24 h, fogging tends to occur on the surface of the optical glass. The moisture permeability is preferably 1.5 g / m ² · 24 h or less, and more preferably 0.1 g / m ² · 24 h or less.

  The method described in JIS Z 0222 is that the outside of the container is exposed to an environment where air circulates at a temperature of 40 ± 1 ° C., a relative humidity of 90 ± 2%, and about 1 m / second, and the inside of the container is filled with dry air. Then, after exposure for 24 hours, the increase in mass of the container was measured, and the increase in mass per surface area of the container was calculated.

A container having a moisture permeability of 10 g / m ² · 24 h or less can be manufactured using a resin laminate containing any one of a metal thin film, an inorganic oxide thin film, and an inorganic nitride thin film.

  As the metal thin film, Al, Ti, Cu or the like can be used. In particular, Al is preferable because it is lightweight and inexpensive.

As the inorganic oxide thin film, SiO ₂ , Al ₂ O ₃ or the like can be used.

Si ₃ N ₄ or the like can be used as the inorganic nitride thin film.

  For the resin layer of the resin laminate, nylon, polypropylene, polyethylene, low density polyethylene, polyethylene terephthalate, or the like can be used.

The optical glass package of the present invention may be filled with dry air or inert gas (N ₂ , Ar, etc.) in the container to lower the water vapor pressure in the container. Is more preferable. The reason is that if this method is used, the water vapor pressure can be lowered and the optical glass can be fixed with a container, so that the optical glass is less likely to be damaged by vibrations during transportation. The inside of the container is preferably 0.2 atm or less, and more preferably 0.1 atm or less.

The main cause of fogging the surface of the optical glass is moisture, but CO ₂ can also cause fogging. Therefore, the CO ₂ permeability in the bag-like container is preferably 10 cc / m ² · 24 h · atm or less as measured by the method described in JIS K 7126. More preferably, it is 5 cc / m ² · 24 h · atm or less, and further preferably 0.1 cc / m ² · 24 h · atm or less.

The method described in JIS K 7126 is as follows. First, an apparatus as shown in FIG. 1 is prepared, the test piece 1 and the filter paper 2 are set in the permeation cell 3, and the air in the apparatus is exhausted by the vacuum pump 4. Then, fed from CO ₂ cylinder 5 CO ₂ to CO ₂ feeder 6, and supplies the CO ₂ to the permeation cell 3 from CO ₂ feeder 6 at about 1 atm. Subsequently, the pressure change of the permeated CO ₂ is recorded using the pressure detector 7, and the measurement is continued until the pressure change per unit time becomes a straight line. Finally, the CO ₂ permeability is calculated from the slope of the straight line.

  The optical glass package of the present invention is an optical glass having low water resistance, for example, a glass having a weight loss of 0.02% by mass or more in a powder method water resistance test described in Japan Optical Glass Industry Association Standard (JOGIS). Even when packed, cloudiness is unlikely to occur.

  The powder method water resistance test described in the Japan Optical Glass Industry Association Standard (JOGIS) is a method in which a glass crushed to a particle size of 425 to 600 μm is taken in a specific gravity gram, placed in a platinum basket, and placed in a round bottom flask with a quartz glass cooler. It is immersed in 80 mL of pure water (pH 6.5 to 7.5), heated in boiling water for 60 minutes, and weighs the mass after drying at 120 ° C. The greater the decrease, the lower the water resistance. Show.

  When the optical glass package of the present invention is packed in a state where the optical glass is placed on a tray 10 with a partition 10a for avoiding contact between the optical glasses, as shown in FIG. Since they do not easily collide with each other, it is preferable that the surface is not easily damaged. Further, a plurality of trays may be stacked and packed.

  The tray is preferably made of resin or rubber, and polypropylene, ABS, polydifluoroethylene, polytetrafluoroethylene, polyethylene, polyvinyl chloride, polyfluorocarbon, EPDM rubber, silicone rubber, or the like can be used.

  The optical glass packed in the optical glass package of the present invention is taken out of the container after unpacking and formed into an optical component by press molding or the like.

  Incidentally, after the optical glass is formed into an optical component, a film such as an antireflection film is formed on the surface, so that the surface of the optical component is hardly fogged even when exposed to a high temperature and humidity environment for a long period of time.

  Hereinafter, the present invention will be described in detail using examples.

  Table 1 shows the packaging bodies of Examples 1 and 2 and the comparative example.

[Example 1]
The package of Example 1 was produced as follows.

  First, a three-way plain bag (200 × 250 mm) made of a resin laminate in which polyethylene terephthalate / polyethylene / aluminum / polyethylene / low-density polyethylene was laminated from the outside was prepared.

Next, a total of 100 spherical optical glasses having a diameter of about 4 mm were placed on a 100 × 100 × 5 mm tray, 10 in each direction. The optical glass has a SiO ₂ —B ₂ O ₃ —RO-based composition and is a glass having a mass loss of 0.03 mass% in the powder method water resistance test described in the Japan Optical Glass Industry Association Standard (JOGIS). The thing which consists of was used. The trays were made of polypropylene purchased from Adachi Shin Sangyo Co., Ltd.

  Finally, in a state where two trays on which optical glass is placed are stacked and placed in the bag-like container, the air in the container is discharged using a vacuum packaging machine, and the bag-like container is removed by thermocompression bonding. A package was produced by tightly wrapping.

[Example 2]
The package of Example 2 was prepared in the same manner as in Example 1 except that a three-way plain bag made of a resin laminate in which silica-deposited polyethylene terephthalate / nylon / CPP polypropylene was laminated from the outside was used as a container.

[Comparative example]
The package of the comparative example is packed in the same manner as in Example 1 except that a three-way plain bag made of a resin film in which nylon-based polyamide, polyethylene, low-density polyethylene, and a polyethylene-based special laminate film are laminated is used as a container. The body was made.

For each of the produced packages, the moisture permeability of the container material, the CO ₂ permeability, and the surface properties of the optical glass after the acceleration test were evaluated. The results are shown in Table 1.

  As is clear from Table 1, in the packages of Examples 1 and 2, fogging was not observed in the optical glass even when the accelerated test was performed, but in the comparative package, fogging was generated in the optical glass by the accelerated test. did.

  The moisture permeability of the container material was measured using the method described in JIS Z 0222 described above.

The CO ₂ permeability of the container material was measured using the method described in JIS K 7126.

  Glass surface properties are measured by holding the package prepared in an environment of temperature 60 ° C. and relative humidity 90% for 24 hours, then opening the package and visually determining the surface of the optical glass. Those that could not be seen were judged as “◯”, and those that were cloudy were judged as “x”.

  Since the optical glass package of the present invention can suppress the occurrence of fogging on the surface of the optical glass, it is suitable for producing optical components such as lenses, prisms, and optical receptacles from the packed optical glass. .

Is an explanatory view showing an apparatus for measuring the permeability of CO _2. It is a perspective view which shows an example of a tray.

Explanation of symbols

1 test piece 2 filter paper 3 permeation cell 4 vacuum pump 5 CO ₂ cylinder 6 CO ₂ feeder 7 pressure detector 10 trays 10a partition

Claims (3)

In a state where the optical glass is placed on a tray with a partition for avoiding contact between the optical glasses, only the optical glass and the tray are enclosed in a bag-like container, The container is made of a resin laminate containing any one of a metal thin film, an inorganic oxide thin film, and an inorganic nitride thin film, and the moisture permeability of the container measured by the method described in JIS Z 0222 is 10 g / m ² · 24 h or less , and optical glass packaging body, wherein the permeability of CO ₂ was measured by the method described in JIS K 7126 is not more than ^{10cc / m 2 · 24h · atm} . The optical glass package according to claim 1, wherein the inside of the container is sealed in a reduced pressure environment. According to claim 1 or 2 weight loss measured by the powder method water resistance test described in the Japanese Optical Glass Industrial Standard is characterized by being obtained by Mitsutsutsumi the optical glass not less than 0.02 wt% Optical glass package.