JPH0542376B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for manufacturing optical glass elements for mass-producing high-precision optical glass elements by press molding, which does not require a polishing process after press molding. Conventional technology In order to directly press and mold high-precision optical glass elements, the mold material must be stable even at high temperatures, have excellent oxidation resistance, and is inert to glass, so that the shape accuracy collapses when pressed. It is necessary to have excellent mechanical strength so that it does not occur, but on the other hand, it must also have excellent workability and be able to be precisely processed easily. Silicon carbide (SiC) or silicon nitride (Si ₃ N ₄ ) was used, and further published in JP-A-59-121126.
A mixed material of titanium carbide (TiC) and metal described in the above publication is also being considered. Problems to be Solved by the Invention However, conventional mold materials that satisfy all of the above conditions have not been obtained. For example, when using SiC and Si ₃ N ₄ as the mold material,
Although it is very hard and has excellent mechanical strength, it has the disadvantage of poor workability and being susceptible to reactions with lead (Pb) and alkali elements, which are constituents of optical glass elements. Furthermore, mixed materials of TiC and metal tend to react with optical glass elements, making them unsuitable as mold materials. As described above, conventional mold materials do not satisfy all of the above-mentioned requirements for mold materials. Therefore, the life of the mold is short, and high-precision optical glass elements cannot be mass-produced by press molding. In view of the above problems, it is an object of the present invention to provide a press-molding mold that enables mass molding of high-precision optical glass elements with good optical performance by direct press-molding. Means for Solving the Problems In order to solve the above problems, the present invention uses cemented carbide or various cermets mainly composed of WC, which has good workability and excellent mechanical strength, as a base material for press molding molds. As, 2.0% by weight on its press surface −80
Pd-Re alloy containing wt% Re or 2.0
Thin film based on Pd-Re alloy with Re of wt% - 80 wt%, Pd-Os alloy containing Os of 2.0 wt% - 75 wt% or 2.0 wt% - 75 wt%
Thin film mainly composed of Pd-Os alloy containing Os,
Pd-Ru alloy containing 2.0wt%-80wt% Ru or 2.0wt%-80wt% Ru
Thin film based on Pd-Ru alloy, 2.0% by weight -75
A mold is prepared by coating a thin film mainly composed of a Pd-W alloy containing 1.0% by weight of W or a Pd-W alloy containing 2.0% to 75% by weight of W, and this mold is used. This has made it possible to press-form highly accurate optical glass elements with good optical performance. Effects According to the present invention, with the above-described configuration, it is possible to obtain a mold that satisfies all of the above-mentioned requirements, which could not be achieved with conventional mold materials, and by using this mold, an optical glass element can be directly pressed. This makes it possible to mold the material. Example Hereinafter, an example of the method for manufacturing an optical glass element of the present invention will be described with reference to the drawings. A pair of press molding molds for optical glass elements consisting of upper and lower molds having concave pressing surfaces with radii of curvature of 46 mm and 200 mm, respectively, was made from cemented carbide mainly composed of WC with a diameter of 20 mm and a thickness of 6 mm. .
The press surfaces of these molds were polished to a mirror surface using ultrafine diamond abrasive grains. Next, on this mirror surface, a Pd-Re alloy thin film, a Pd-Os alloy thin film with a composition shown in Table 1,
A press molding mold was prepared by coating a pd-Ru alloy thin film or a Pd-W alloy thin film. A cross-sectional view of the mold thus produced is shown in FIG. In Fig. 1, 11 is the base material, 12 is the Pd-Re alloy thin film coated on the press surface,
Pd-Os alloy thin film, Pd-Ru alloy thin film or
This is a Pd-W alloy thin film. This mold is set in the press molding machine shown in FIG. In FIG. 2, 21 is an upper mold, 22 is a lower mold, 23 is a heater for the upper mold, 24 is a heater for the lower mold, 25 is a piston cylinder for the upper mold,
26 is a piston cylinder for the lower mold, 27 is a supply glass element block, 28 is a jig for supplying glass elements,
29 is an outlet for taking out the press-molded optical glass element, 210 is a preheating furnace for the supplied glass element block, and 211 is a cover. Next, a lump 27 made of a lead oxide-based optical glass consisting of 70% by weight of lead oxide (PbO), 27% by weight of silica (SiO), and the rest being trace components processed into a spherical shape with a radius of 10 mm was heated in a preheating furnace 210. rear,
Upper and lower molds 21 and 22 held at 520℃
Place it on the lower mold 22 of the machine and put it in a nitrogen atmosphere to weigh about 40Kg/cm ^2.
The upper and lower molds are then cooled down to 300°C, and the press-molded optical glass element is taken out from the outlet 29, and the optical glass element is press-molded. Complete the process. After repeating the above process and completing the 1000th press, remove the upper and lower molds 21 and 22 from the press molding machine, observe the state of the pressed surface with an optical microscope, and check the surface roughness of the pressed surface at that time (RMS value,
Å) was measured to evaluate the accuracy of each mold.
Furthermore, as a comparative experiment, a mold of a conventionally used silicon carbide (SiC) sintered body was prepared and set in the press molding machine shown in Fig. 2, and the press molding process of the optical glass element described above was repeated 1000 times. The test was repeated several times and the mold accuracy was evaluated in the same way. In addition, the above-mentioned press test was also conducted on molds coated with platinum (Pt) sputter films and Pd sputter films instead of the various alloy sputter films used in the molds of the present invention. The results of the press test using the mold of the present invention are shown in Table 1, and the results of the press test using the mold for comparison are shown in Table 2.

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[Table] Table 2, conventionally used SiC of sample No. 116
In a mold using a sintered body, after pressing the glass several times, the mold and glass reacted, and the glass adhered to the pressed surface, making it completely unusable. Also, as in Table 2, Sample No. 117 and 118
Glass does not adhere to molds coated with Pt or Pd spatter film, but after 1000 presses, the surface roughness (RMS value) is 253.5.
Å and 192.5 Å, which is extremely rough and the surface becomes cloudy, making it impractical. As is clear from Table 1, for the above comparative samples, the mold of the present invention, that is, the base material is a cemented carbide mainly composed of WC, and the press surface is coated with 2.0% to 80% of the weight. Pd-Re alloy containing Re or Pd- containing 2.0 wt%-80 wt% Re
Thin film based on Re alloy, Pd-Os alloy containing 2.0 wt%-75 wt% Os or 2.0 wt%
- Thin film based on Pd-Os alloy containing 75 wt% Os, Pd-Ru alloy containing 2.0 wt% - 80 wt% Ru or 2.0 wt% - 80 wt% Ru
Thin film mainly composed of Pd-Ru alloy containing Ru,
Pd-W alloy containing 2.0wt%-75wt% W or Pd containing 2.0wt%-75wt% W
- When using a mold coated with a thin film mainly composed of W alloy, the surface roughness remains almost unchanged from before pressing even after 1000 presses.
The life of the mold has been significantly extended, and it has become possible to press-mold high-precision optical glass elements in large quantities. Furthermore, as is clear from Table 1, when at least one element, Os or Ta, is added to the Pd-Re alloy thin film up to 10% by weight each, the surface roughness after 1000 presses becomes smaller than that of Os or Ta. It can be seen that as the content increases, the size becomes smaller and the mold life is further extended. Similarly, 10% by weight each of at least one element of Re or Ta was added to the Pd-Os alloy thin film.
It can be seen that the surface roughness after 1000 presses becomes smaller as the Re or Ta content increases, and the mold life is extended even when the Re or Ta content is increased. Furthermore, if at least one element of Re, Os or Ta is added to the Pd-Ru alloy thin film or Pd-W alloy thin film up to 10% by weight each, the surface roughness after 1000 presses will be lower than that of Re, Os or Ta. It can be seen that as the content increases, the size becomes smaller and the mold life is further extended. As described above, the mold of the present invention satisfies all of the requirements for direct press molding of high-precision optical glass elements as described above, and has a significantly longer mold life than conventional molds, allowing for high-precision optical glass elements. It has become possible to press-mold optical glass elements in large quantities. In addition, in order to explain the present invention, in the examples, a mold using a cemented carbide whose main component is WC as the base material of a press molding mold was taken as an example, but TiN, TiN,
The base material is a cermet whose main component is TiC, Cr ₃ C ₂ or Al ₂ O ₃ , and 2.0% by weight is applied to the pressed surface.
Pd-Re alloy containing 80 wt% Re or
Thin film based on Pd-Re alloy containing 2.0 wt% - 80 wt% Re, 2.0 wt% - 75 wt%
Pd-Os alloy containing Os or 2.0 wt%-75
Thin film based on Pd-Os alloy containing 2.0 wt.% Os, pd− containing 80 wt.% Ru
Thin film based on Ru alloy or Pd-Ru alloy containing 2.0wt%-80wt% Ru, 2.0wt%
- Pd-W alloy containing 75% W by weight or
Even if a mold is coated with a thin film mainly composed of a Pd-W alloy containing 2.0% to 75% W, the mold life is similarly extended and mass production of high-precision optical glass elements is possible. It became possible to Effects of the Invention As described above, in producing the press-molding mold for the optical glass element of the present invention, cemented carbide and cermet are used as the base material, and the press surface is
Pd-Re alloy containing 2.0wt%-80wt% Re or 2.0wt%-80wt% Re
Thin film based on Pd-Re alloy, 2.0% by weight -75
Thin films based on Pd-Os alloys containing % by weight of Os or Pd-Os alloys containing from 2.0% to 75% by weight of Os, pd-Ru containing from 2.0% to 80% by weight of Ru Alloy or 2.0wt%-80wt%
Thin film mainly composed of Pd-Ru alloy containing Ru, Pd-W containing 2.0 wt% - 75 wt% W
Press-molding of an optical glass element that satisfies all of the above-mentioned requirements as a mold material by coating a thin film mainly composed of an alloy or a Pd-W alloy containing 2.0% to 75% by weight of W. In order to manufacture high-precision optical glass elements at low cost and in large quantities,
This is an extremely useful invention.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a press molding mold for an optical glass element of the present invention, and FIG. 2 is a schematic diagram of a press molding machine incorporating the press molding mold for an optical glass element according to an embodiment. 11... Base material, 12... Pd-Re alloy coated on the press surface, Pd-Os alloy, Pd-
Sputter thin film of Ru alloy or Pd-W alloy.

Claims (1)

[Claims] 1. A material with heat resistance and excellent workability is used as a base material for a press molding die, and palladium containing 2.0% to 80% by weight of rhenium (Re) is applied to the press surface. Rhenium (Pd-Re) alloy thin film, palladium-osmium (Pd-Os) alloy thin film containing 2.0 wt% - 75 wt% osmium (Os), 2.0
Palladium-ruthenium (Pd-Ru) alloy thin film containing 80 wt% ruthenium (Ru) or 2.0 wt% - 75 wt% tungsten (w)
Palladium-tungsten (Pd-W) containing
A method for manufacturing an optical glass element, characterized by press-molding it in a mold coated with a thin alloy film. 2 The base material of the press molding die is a cemented carbide whose main component is tungsten carbide (WC), or titanium nitride (TiN), titanium carbide (TiC), chromium carbide (Cr ₃ C ₂ ), or alumina (Al ₂ O ₃ ) is used as a main component. 2 O 3 ). 3 Pd-Re coating on press molding mold
2. The method for producing an optical glass element according to claim 1, wherein the thin film contains at least one element of Os or tantalum (Ta) within 10% by weight. 4 Pd-Os coating on press molding mold
2. The method for manufacturing an optical glass element according to claim 1, wherein the thin film contains at least one element of Re or Ta within 10% by weight. 5 Pd-Ru coating on press molding mold
2. The method for producing an optical glass element according to claim 1, wherein the thin film contains at least one of Re, Os, or Ta within 10% by weight. 6 Pd-W coating on press molding mold
2. The method for manufacturing an optical glass element according to claim 1, wherein the thin film contains at least one of Re, Os, or Ta in an amount of 10% by weight or less.