JP3094011B2 - Optical glass material and method for manufacturing optical element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical glass material used for forming a glass optical element by hot pressing and a method for manufacturing an optical element using the material.

[0002]

2. Description of the Related Art It has been widely practiced to heat and soften an optical glass material and press-mold it into a desired shape with a molding die to obtain an optical element that does not require grinding and polishing. In the case of the molding method using the hot press, it is important to satisfy the surface shape and surface characteristics (surface roughness, appearance, etc.) required for the optical lens for image formation. It is necessary to use a molding material having high oxidation resistance, high precision, poor wettability with a glass material, and good mold release properties. However, there is a limit to completely preventing fusion between the mold and the glass material only by improving the mold material.
It can only be formed with a limited type of glass material. Attempts have been made to prevent fusion by focusing on the glass material side.
A proposal has been made as described in JP-A-2023. This is to form a continuous film of carbon having a thickness of about 1 to 100 nm on a molding surface of a glass material adjusted to a predetermined shape and capacity by grinding, polishing, or the like so that the surface of the glass material is covered with the film. By doing so, it is intended to prevent fusion between the glass material and the molding die.

[0003]

The molding surface of a glass material flows and deforms when pressed by a molding die, but the continuous carbon film formed on the molding surface has no fluidity and is deformed. Therefore, when the coating attempts to follow the molding surface of the molding die, the coating necessarily cracks. Therefore, in a state where the glass material is pressed by the molding die, there are a portion where the mold is in direct contact with the glass material and a portion where the carbon material is interposed. For this reason, there is a problem in that the mold and the glass material are fused at the portion in direct contact. In addition, between the part in direct contact and the part via the carbon coating, a step corresponding to the thickness of the carbon coating occurs on the surface of the glass molded product, which causes poor appearance during molding and deterioration of optical characteristics. . Furthermore, when the glass material is released from the mold, the carbon coating may peel off (adhere) to the molding surface of the mold, and when performing continuous molding, the carbon coating that has peeled off may form a glass molded product. This may cause poor appearance.

[0004] In addition, it is necessary to consider the surface defect of the glass material as a factor of the fusion between the mold and the glass material. The glass material before forming the carbon film subjected to grinding and polishing has minute surface defects such as latent scratches and mechanically weak scratches hidden in the surface layer. Further, in many cases, a chemically unstable reaction layer called scorch is formed on the surface of the glass material at the time of grinding and polishing. Due to these surface defects, the surface state of the glass material becomes unstable, and cracks are generated from latent scratches on the surface layer during the press molding after forming the carbon coating (the latent scratches progress to cracks), and the carbon coating and glass There is a problem that the cracked portion of the material surface is fused to the surface of the mold, and a problem that the optical characteristics of the optical glass element from which the carbon coating is removed after molding is deteriorated (for example, the transmittance is reduced).

The present invention has been made in view of the above-mentioned problems, and there is no fusion between a mold and a glass material during press molding.
An object of the present invention is to provide an optical glass material that does not cause a surface defect of a glass material before press molding to an optical element, and a method for manufacturing an optical element using the material.

[0006]

Means for Solving the Problems In order to achieve the above object, according to the present invention, when a heat-softened optical glass material is press-formed between a pair of molds to produce an optical element molded product,
An optical glass material from which surface defects have been removed by ion implantation is used for the molding surface.

In the present invention, at least ions, for example, carbon ions, are implanted into the molding surface to form an optical glass material having a sputtering effect on the molding surface and a plastic flow on the surface. The optical glass material formed by the ion implantation is heated and softened, press-molded between a pair of dies, taken out of the dies, and then annealed to obtain a desired optical element molded product. Here, the term “ion implantation” means that, for example, carbon ions may be accelerated and implanted, or ions other than carbon may be accelerated and implanted in an atmosphere containing carbon to simultaneously implant desired carbon. You may make it inject | pour.

[0008]

In the optical glass material having the above-mentioned structure, for example, when a carbon component is injected into a molding surface, (1) the wettability with the mold is deteriorated by the carbon component on the molding surface, and the carbon material is removed from the mold even in press molding at high temperature. With excellent mold release properties. Since the carbon component exists in the vicinity of the glass material surface in a state of low electrical polarity such as hydrocarbon (Chemical Formula 1), the carbon component is hardly bonded to a mold material which has been heated to a high temperature and has increased activity. Is increasing the character.

[0009]

Embedded image

(2) Since the carbon component and the glass component on the molding surface are in a mixed state, the carbon component also flows together with the glass component during press molding. Therefore, since the glass component and the carbon component are always in contact with the entire molding surface of the mold, there is no occurrence of fusion or poor appearance.

(3) Since the carbon component exists in the glass material in a non-equilibrium state, it easily moves inside the glass. Therefore, it is oxidized in the annealing step and is easily separated as CO gas.

A modified layer containing a non-equilibrium carbon component in a glass component is useful for enhancing the releasability during molding, but causes a change in optical properties when left on the surface of a molded product. There is a risk. Therefore, it is better that the modified layer disappears after molding. Since the molded optical element is subjected to an annealing process for removing distortion and adjusting optical constants, it is desirable that the reformed layer be eliminated by the annealing process.

As described above, for example, a carbon component implanted as ions is easily separated by heating, so that at least the carbon component is not oxidized in the heating softening step before the pressing step. It is preferable that the layer exists up to a depth of 20 nm or more. Also, even if the glass flows in the pressing step, it is necessary to keep the carbon component on the surface of the glass material at all times. The thickness of the modified layer must be determined. That is, the shape of the glass material and the shape of the desired molded product are significantly different,
When the amount of deformation is large, it is necessary to increase the thickness of the modified layer. On the other hand, in order for the carbon component to be released by the annealing treatment, it is necessary that the carbon component is kept within a range of about 200 nm in depth from the surface of the molded article after molding.

In consideration of these points, it is desirable to determine the thickness of the modified layer of the glass material. In some cases, it is better to partially change the thickness of the modified layer according to the deformation amount of the front and back surfaces of the glass material or the glass forming surface. In some cases, the modified layer may be provided only on a portion where fusion is likely to occur, or only on one surface.

Means for producing an optical glass material containing the glass component and a non-equilibrium carbon component include the following (1) and (2). (1) Carbon is ionized and accelerated, and directly penetrates into the molding surface (surface layer) of the glass material. (2) In an atmosphere containing carbon, carbon excited by an accelerated ion beam other than carbon is caused to penetrate into the surface layer of the glass material together with ions other than carbon.

The operation of the creation means will be described below. (1) Since the ion implantation method is a non-equilibrium process, carbon and other ions penetrating into the glass material are present in a non-equilibrium state. As described above, ions and carbon such as carbon ions existing in a non-equilibrium state in the glass component easily move inside the glass. When the same component as the optical glass-containing component is ionized and implanted, this component is uniformly diffused into the glass by annealing. In order not to unnecessarily lengthen the annealing time, for example, O,
Alternatively, it is preferable to use a material having a high diffusion rate such as Na or K. On the other hand, when a component that is gasified in a temperature region equal to or lower than the annealing point of the optical glass is ionized and injected, this component is separated from the surface of the glass material by annealing. It is necessary that such a component does not easily dissolve into the glass, and is preferably an inert gas such as He, Ne, or Ar, or a gas component such as H ₂ or N ₂ . In order to separate the molded product, it is necessary that the molded product be kept at a depth of about 200 nm from the surface of the molded product, as described above. In order to make carbon or the like penetrate into the glass, other methods such as an ion exchange method and a carburizing method can be considered in addition to the ion implantation method.However, since these methods are equilibrium processes, carbides are contained in the glass. Is formed and stabilized, so that carbon remains in the glass even after the annealing treatment, and the optical characteristics deteriorate.

(2) In the ion implantation method, the depth of the reformed layer can be extremely accurately controlled by the ion accelerating voltage, and the degree of reforming can be extremely accurately controlled by the ion implantation amount, and the reproducibility is improved. As described above, the depth of the modified layer is determined in consideration of the detachment at the time of annealing and the flow amount of glass, and therefore, the ion implantation method is optimal.

(3) At the same time as the ion implantation, a sputtering action occurs on the glass material forming surface, so that surface defects such as latent scratches and burns on the glass material surface are removed.

(4) By the above-mentioned sputtering action,
Since dust and dirt attached to the surface of the glass material are removed, it is not necessary to clean the glass material before molding.

(5) At the time of ion implantation, when high-speed ions collide with atoms inside the glass, heat is locally generated,
A plastic flow is generated on the surface of the glass material to produce a smoothing effect. Thereby, latent scratches generated in the grinding process are removed.

[0021]

(Embodiment 1) FIG. 2 shows a glass material 1 after grinding and polishing used in Embodiment 1 of the present invention. The shape of the glass material 1 is biconvex, one surface is R16.9 mm, and the other surface is R
97.3mm, outer diameter φ11.8mm, medium thickness 1.8m
m, the margin is 0.56 mm. The glass type is SK type, the components are Si, O, Ba, Ca, etc., and the transition point is 550.
° C and a softening point of 670 ° C. The surface roughness is R
It is finished to a max of 0.02 μm.

Using a commercially available ion implantation apparatus whose schematic diagram is shown in FIG. 3, a modified layer 2 was formed on the surface of the glass material 1 as shown in FIG. Specifically, as shown in FIGS. 3 and 4, the glass material 1 was held on a plate 3 made of the same glass material, and set in the ion implanter 4. Then, CH ₄ gas is introduced from the gas inlet 5 at the lower part of the apparatus, and the pressure becomes 3 × 10 ⁻⁵ T.
Adjusted to orr. Subsequently, an N ₂ gas is introduced from a gas inlet 6 in the upper part of the apparatus, and an ion generator 1 composed of a filament 7, a coil 8, an extraction electrode 9, and the like.
At 0, the ions are ionized and passed through a mass analyzer 13 composed of a magnet 11, a slit 12, etc., and an accelerator 16 composed of an accelerating tube 14, an XY scanning electrode 15, and the like. × 10 ¹⁵ ion
/ Cm ₂ . At this time, the CH ₄ gas 18 colliding with the N ions 17 is dissociated and excited, and carbon of the CH ₄ gas 18 is injected into the glass material 1 together with the N ions 17. In this way, as shown in FIG. 1, the modified layer 2 is formed on the surface of the glass material 1.

FIG. 5 shows the result of analyzing the modified layer 2 of the glass material 1 by X-ray photoelectron spectroscopy (XPS). About 1
To a depth of 80 nm, a small amount of N (about 1 atm
%) Is present. Further, to a depth of about 150 nm, carbon (about 1 atm%) exists and Si (about 10 atm%) exists.
%) And O (about 16 atm%), but other Ba,
Ca is scarcely present. In the portion deeper than 180 nm, the amount of carbon suddenly decreases and the amounts of Ba and Ca increase, and the state is the same as that of the glass material 1 before ion implantation (that is, the surface state after polishing shown in FIG. 2). . The surface roughness was 0.03 μm or less.

The wettability between the glass material 1 on which the modified layer 2 was formed and each type of mold material was examined. Specifically, the glass material 1 was placed on various molds and heated to near the softening point, and the wetting angle at this time was examined in the air atmosphere and the N2 gas atmosphere. Table 1 shows the results. For comparison, Table 1 also shows the results of those subjected to only grinding and polishing.

[0025]

[Table 1]

The glass material 1 of this embodiment has a wetting angle with any mold material of 70 ° or more, which indicates that the wettability is extremely poor. Most of the change in wettability is caused by carbon, but it is considered that the change is also caused by N ions implanted at the same time. This is mainly due to the change in the surface tension of the glass due to the atmosphere in which the wettability is examined. The presence of components other than the gas contained most in the atmosphere gas on the surface of the glass material 1 further enhances the glass properties. The surface tension can be increased to deteriorate the wettability. In the present embodiment, since N ions are present on the surface of the glass material 1, the wetting angle is larger in the atmosphere than in the N ₂ gas atmosphere.

Further, 2,000 pieces of the above glass material 1 were prepared, and the glass material 1 and a molding die (c) were prepared in an air atmosphere.
-BN) was heated to 700 ° C (above the softening point) to perform continuous molding. As a result, the shape precision of the manufactured glass lens is all PV value 0.1 μm or less,
The glass material 1 was never fused to the molding die. Next, the molded article (glass lens) was cooled to about room temperature, then placed in an annealing furnace, heated to 530 ° C. over 30 minutes, and kept at 530 ° C. for 15 minutes. Then, after slowly cooling to 430 ° C. over 2 hours, the annealing furnace was turned off and cooled naturally in the furnace. In the present embodiment, the temperature is raised from about room temperature. However, the molded product may be placed in an annealing furnace while the temperature of the molded product is high and kept at 530 ° C. for 15 minutes.

The transmittance of the glass immediately after molding was 86%, which was slightly white and cloudy, but was 91% by the subsequent annealing treatment, and no problem occurred in optical characteristics. For reference, the annealed glass was XP
The result analyzed by S is shown in FIG. Although carbon exists on the outermost surface, this is contamination (dirt) that the outermost surface adsorbed from the atmosphere before analysis, and it can be seen from the depth direction that carbon is almost eliminated. Similarly, N almost disappeared, and it was confirmed that the state returned to almost the same as that of the glass not injected (see FIG. 7).

Further, the glass material 1 of the present embodiment was stored in the air for three months, but no scorching occurred on the surface. The SK-based glass material is liable to cause burns by causing a chemical reaction with the moisture adsorbed on the surface, but the ion-implantation treatment deteriorates the wettability with water and becomes a SiO ₂ rich state with high chemical durability. Thus, the occurrence of burns could be prevented.

Further, the above-mentioned ion-implanted glass material 1
The measured Knoop hardness was 620, and the one without ion implantation was 580, indicating that the hardness was also improved. This is because the ions enter the surface layer of the glass material 1 and forcibly expand the interatomic distance, and heat is generated when the ions having high energy with high energy collide with the atoms inside the glass, resulting in rapid heat quenching. This is because, due to the presence, a compressive stress is generated in the surface layer of the glass material 1, so that the mechanical strength is increased. as a result,
There is also an effect that a problem that cracks are generated in the glass surface layer at the time of conventional press molding and the cracked portions are fused to the surface of the mold is less likely to occur.

In the present embodiment, the material of the plate 3 on which the glass material 1 is placed is SK-based glass of the same material as the glass material 1 because the plate 3 is also sputtered when N ions are implanted. Part of the plate 3 is driven into the surface of the glass material 1 so as not to cause a change in optical characteristics at that time, but the material of the plate 3 is quartz glass (pure SiO ₂ ).
In this case, a further SiO ₂ rich state can be formed on the surface of the glass material 1, and an improvement in chemical durability can be expected.

Regarding the ion implantation amount, 1 × 10 ¹² io
If n / cm ² -1 × 10 ¹⁹ ion / cm ² and the acceleration voltage are selected from the range of 10-110 keV, they have sufficient mold releasability when the wetting angle is in the range of 65-95 °. Similar effects can be obtained. Injection volume is 1 × 10 ¹²
ion / cm ² and acceleration voltage is 10 keV
If it is less than 1, the effect of changing the wettability of the glass is not sufficient. When the implantation amount exceeds 1 × 10 ¹⁹ ion / cm ² and the acceleration voltage exceeds 110 keV, it becomes difficult to release the implanted ions in a short time by the annealing treatment, and the ions remain on the molded article. The possibility of deteriorating optical properties arises due to the carbon component.

(Comparative Example) When a glass material which had been subjected to grinding and polishing and was not subjected to ion implantation was formed under the same conditions as in the above embodiment, the glass was fused to the mold. In addition, in the temperature range where fusion does not occur, the shape accuracy of the molded product is less than PV.
Those having a value of 1 μm or less could not be prepared.

[0034]

Second Embodiment FIG. 8 shows a method of manufacturing an optical glass material according to a second embodiment. The glass type is the same SK type as in the first embodiment. First, it was processed into the same shape as that shown in FIG. 2 by CG (curve generator) grinding. The surface roughness is Rmax 4 to 6 μm. Next, the glass material 19 is placed on the same SK glass plate 20 and
The r ions 21 are accelerated at an acceleration voltage of 20 keV and an implantation amount of 2 × 10 ¹⁸
ion / cm ² . In this step, since the acceleration voltage is relatively small, the sputtering action is large,
The grinding liquid attached to the surface of the glass material 19 and the cracked surface layer during the grinding process are removed. As a result,
The surface roughness was improved to about Rmax 0.3 μm.

Subsequently, the Kr ions 21 are supplied with an accelerating voltage of 70 k.
The injection was performed at eV and an injection amount of 1 × 10 ¹⁵ ions / cm ² . At that time, CH ₄ gas 22 was introduced, and the pressure was 5 × 10 ⁻⁵ To.
When adjusted to be rr, the CH ₄ gas 22 that has collided with the Kr ions 21 is dissociated and excited, and carbon of the CH ₄ gas 22 is injected into the glass material 19 together with the Kr ions 21. As a result, the surface accuracy was further improved to Rmax 0.08 μm.

The modified layer of the glass material 19 for molding produced by the above method was evaluated by XPS. As a result, a small amount of Kr was present up to a depth of about 60 nm, and carbon was also present. Then, as in the first embodiment, S
Although i and O existed, other Ba and Ca hardly existed.

As a result of molding and annealing this glass material 19 under the same conditions as in the first embodiment, a non-defective product having no fusion in the mold, a shape accuracy PV value of 0.1 μm or less, and a transmittance of 90% or more was obtained. .

In this embodiment, when performing ion implantation,
At the same time, by taking advantage of the fact that a sputtering action also occurs, it adheres to glass, removes dirt and burns, and has an effect of preventing deterioration of optical characteristics and fusion with a mold. Also,
The washing step can be omitted. When the ion accelerating voltage is 30 keV or less, the sputtering action is larger than the implantation action, and ions having a larger mass have a larger sputtering action. If the conditions for ion implantation are set in consideration of these factors, a sufficient sputtering effect can be obtained in a short time, and the same effect as in the present embodiment can be obtained.

In this embodiment, when ions having high energy with high speed collide with atoms inside the glass, heat is locally generated, and plastic flow is generated on the surface of the glass, so that the smoothing effect is obtained. Utilizing that
Cracks generated in the grinding process are removed. As a result, deterioration of optical characteristics and fusion with a mold can be prevented, and the steps of etching and polishing can be omitted. Therefore, in the present embodiment, CG grinding → ion implantation → molding →
It is possible to manufacture a glass material having good releasability by an extremely simple process of annealing. When the acceleration voltage of the ions is 50 keV or more, the smoothing effect is large, and ions having a large mass have a large smoothing effect. If the conditions for ion implantation are set in consideration of these factors, a sufficient smoothing effect can be obtained.

In this embodiment, the glass material 19 is ground before the pouring. However, if the initial pouring conditions are set appropriately and the sputtering action is further increased, a direct press called press material is used. Product (The glass that flows out of the crucible is cut with a shear and embossed.
There is a defect called a shear mark and adhesion of a release agent. )
Can be smoothed by removing surface defects and adhesions of the sapphire, and the manufacturing process can be further simplified. As a result, significant cost reduction can be achieved.

[0041]

Embodiment 3 In the present embodiment, an apparatus of the type in which the mass analyzer 13 is omitted from the ion implantation apparatus 4 shown in FIG. 3 is used. A flat glass plate (φ12 mm, thickness 4 mm) obtained by fine-grinding the surface of SF glass (main components: Si, O, Pb, transition point 460 ° C, softening point 590 ° C) and finishing the surface roughness to Rmax 0.5 μm Is used as a glass material 23, and this glass material 23 is a plate 2 of the same SF-based 23 glass.
4 (see FIG. 9). Next, CO gas is introduced from the upper gas inlet 6 to 4 × 10 ⁻⁴ Torr, and the CO gas is dissociated and ionized using thermoelectrons jumping out of the tungsten filament 7. The ions were implanted at an acceleration voltage of 80 keV. In this method, C ions 25 and O ions 26
At the same time, the glass material 23 is injected.

The thickness of the modified layer of the glass material 23 for molding manufactured by the above method is about 250 nm, and the surface roughness is R
max was 0.09 μm. Using the glass material 23 for molding, the glass material 23 is placed in an N ₂ gas atmosphere.
Is heated to 660 ° C., and the molding die (made of zirconia) is heated to 490 ° C. to form a biconvex lens (R ₁ : 19.4 mm, R ₂ : 108).
mm, 3.7 mm thick). As a result, there was no fusion in the mold, and the shape accuracy PV value was 0.1.
Good products having a size of not more than μm were obtained. Next, the molded product (glass lens) is cooled to about room temperature, and then placed in an annealing furnace.
The temperature was raised to 425 ° C. over 0 minutes and kept at 425 ° C. for 15 minutes. Then, after slowly cooling to 300 ° C. over 4 hours, the switch of the annealing furnace was turned off and the furnace was naturally cooled in the furnace. The transmittance of the glass after annealing is 9
0% or more, and there was no mold deterioration.

According to the present embodiment, since carbon itself is ionized and accelerated and injected into the glass material 23, the injection amount and injection depth of carbon can be extremely strictly controlled. In the case of a glass material containing Pb such as SF, Pb may be reduced at the time of ion implantation.
By implanting the O ions 26 at the same time as the step 5, the Pb was not reduced, the glass was deteriorated, and the transmittance did not decrease.

According to the present embodiment, zirconia which is inexpensive and has sufficient strength, hardness and heat resistance can be used as a mold material, so that the life of the mold is greatly extended, and the cost is greatly increased. Reduction could be achieved. In addition,
Conventionally, there was a problem of fusion, and zirconia could not be used as a mold material.

Further, in the present embodiment, the glass material 2
Since a flat plate was used as 3, the cost of the glass material 23 could be significantly reduced. This results in a modified layer thickness of 2
This is because by making the thickness relatively large to 50 nm, it is possible to form without fusion even in the case of a large deformation amount of forming from a flat plate.

As described above, the shape of the glass material is not limited at all, and even if it is a material such as a sphere or a rod,
The present invention can be applied.

[0047]

Fourth Embodiment Using the same flat glass material as in the third embodiment, while introducing CO ₂ gas at a pressure of 5 × 10 ^-5 Torr, first, Si ions are accelerated at an accelerating voltage of 30 k.
Injected at eV. At this time, carbon is also injected at the same time.
Subsequently, O ions were also implanted at 30 keV. At this time, carbon is simultaneously injected.

The modified layer thickness of the glass material for molding produced by the above method was about 20 nm. Using this glass material for molding, the biconvex lens was molded and annealed under the same conditions as in Embodiment 3, and as a result, a good product was obtained.

When Si and / or O are ion-implanted as in this embodiment, SiO _{2 is} added to the surface together with the carbon component.
A rich state can be produced remarkably, and a significant improvement in chemical durability can be expected. Therefore, even if the glass material is stored for a long period of time, no scorching or the like occurs.

[0050]

Embodiment 5 In this embodiment, a LaSF glass is used. This glass material has La, O, B, S components.
i, etc., and has excellent chemical resistance. Further, the glass material has a transition point of 730 ° C. and a softening point of 760 ° C. and has a sharp change in viscosity with respect to temperature, that is, a glass material having a short reed, and is very difficult to mold.

This glass material is ground and polished to obtain a biconvex lens (R ₁ : 19.0 mm, R ₂ : 100 mm, thickness: 4.0 mm).
(1 mm) after finishing the surface roughness to Rmax 0.04 μm, and mounted on the same LaSF glass plate. Then, while adjusting and introducing C ₂ H ₆ gas to a pressure of 2 × 10 ⁻⁴ Torr, Ne ions were accelerated at an acceleration voltage of 30 k
Injected at eV. At this time, carbon is also injected at the same time.

The modified layer of the glass material for molding manufactured by the above method was evaluated by XPS. As a result, a trace amount of Ne was present to a depth of about 80 nm, and carbon obtained from C ₂ H ₆ gas was removed. It was present in large quantities. Among the glass components, L
Although a and Si were present in relatively large amounts, B was scarcely present in the modified layer.

Using the above glass material for molding, the glass material was heated at 770 ° C. in an air atmosphere at a molding die (Al ₂ O).
₃ ) was heated to 740 ° C., and a biconvex lens (R ₁ : 19.
(4 mm, R ₂ : 108 mm, thickness 3.7 mm). As a result, all of the manufactured glass lenses had a PV accuracy of 0.1 μm, and did not fuse to the mold. Next, after the molded article (glass lens) is cooled to about room temperature, it is placed in an annealing furnace, and is cooled for 30 minutes.
The temperature was raised to 00 ° C and maintained at 700 ° C for 1 hour. Thereafter, the temperature was slowly reduced to 630 ° C. over 2 hours, and then the switch of the annealing furnace was turned off and the furnace was naturally cooled in the furnace.

(Comparative Example) When a glass material which had been subjected to grinding and polishing and was not subjected to ion implantation was formed under the same conditions as in the above embodiment, the glass was fused to the mold. Further, in a temperature range in which no fusion was performed, a material having a shape accuracy PV value of 3 μm or less could not be produced.

[0055]

As described above, the optical glass material for molding of the present invention does not fuse with the mold because surface defects are removed. Therefore, since no fusion occurs, the mold temperature can be sufficiently increased, and a high-precision molded product can be easily mass-produced. In addition, glass types that were difficult to mold up to now can be molded, and the degree of freedom in optical design is increased.
The present invention can also be applied to a case where it is difficult to use a glass molded lens in a case where it cannot be used except for a specific glass type. According to the method for manufacturing an optical element of the present invention,
It is possible to mold using a glass material that does not cause fusion without increasing the number of steps as compared with the conventional method.

[Brief description of the drawings]

FIG. 1 is a front view showing a glass material after ion implantation according to a first embodiment of the present invention.

FIG. 2 is a front view showing the glass material after grinding and polishing according to Embodiment 1 of the present invention.

FIG. 3 is a schematic configuration diagram of an ion implantation apparatus used in the first embodiment of the present invention.

FIG. 4 is a front view illustrating the method for manufacturing the glass material according to the first embodiment of the present invention.

FIG. 5 is a graph showing a result of analyzing a modified layer of the glass material (after ion implantation) according to the first embodiment of the present invention by X-ray photoelectron spectroscopy.

FIG. 6 is a graph showing a result of analyzing the glass material (after annealing) according to the first embodiment of the present invention by X-ray photoelectron spectroscopy.

FIG. 7 is a glass material (after polishing) according to the first embodiment of the present invention;
Is a graph showing the result of analyzing by X-ray photoelectron spectroscopy.

FIG. 8 is a front view illustrating a method for manufacturing a glass material according to a second embodiment of the present invention.

FIG. 9 is a front view illustrating a method for manufacturing a glass material according to Embodiment 3 of the present invention.

[Explanation of symbols]

1 glass material 2 reforming layer 4 ion implanter 17 N ion 18 CH ₄ gas 19 glass material 21 Kr ions 22 CH ₄ gas 23 glass material 25 C ions 26 O ions

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C03B 11/00

Claims (2)

(57) [Claims] 1. An optical glass material used for manufacturing an optical element molded product by press-molding a heat-softened optical glass material between a pair of molds, and performing ion implantation treatment on the molding surface to remove surface defects. An optical glass material that has been removed. 2. An optical glass material, in which at least ions are implanted into the molding surface to cause a sputtering action on the molding surface and cause a plastic flow on the surface, are softened by heating and press-molded between a pair of molds. A method for manufacturing an optical element.