JP3469655B2 - Mold for molding composite optical element and method for molding composite optical element - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a mold used in a so-called replica molding method in which a molding surface is transferred to an energy-curable resin by a molding mold to obtain a desired optical surface shape, and the mold is used. The present invention relates to a method for molding a composite optical element.

[0002]

2. Description of the Related Art Conventionally, in a method of manufacturing an aspherical lens having a structure in which a resin layer is laminated on a lens blank, even if parallel light is used to cure the resin, the light is reflected by the mold surface. , Parts with high and low illuminance are created. Therefore, as shown in FIGS. 9A and 9B, the portion of the resin 6 where the illuminance of the reflected light on the surface of the mold 5 and the surface of the lens blank 7 is high completes the curing first, while the weak portion completes the curing later. Therefore, there is a problem that stress is generated in the resin layer and the surface accuracy is deteriorated.

Therefore, in order to solve the above problems, for example, Japanese Patent Laid-Open No. 4-161305 proposes the following invention. As shown in FIGS. 10A and 10B, the invention described above uses the filter 1 so that the illuminance distribution in the resin layer becomes uniform even if ultraviolet rays are reflected multiple times on the surface of the mold 5.
By irradiating the ultraviolet rays adjusted by 1 and 12 to cure the ultraviolet curable resin 6, the lens having the resin layer on the lens blank 7 is obtained.

[0004]

However, the invention described in JP-A-4-161305 has the following drawbacks. That is, when creating a filter to be used, grasp the actual illuminance distribution including the reflected light to the mold without a filter, or use a computer to simulate the state. , And the light transmittance must be determined and created to match (uniformly correct).

However, it is extremely difficult to measure the illuminance distribution in the actually created state, and a measurement error is also added.
Further, even if the simulation is performed, since the reflection and transmission on the surface of the mold, the front surface and the back surface of the lens blank must be taken into consideration, the work becomes considerably complicated. Moreover, this filter is basically required for one mold or a desired lens shape. Therefore, when molding different products, the complicated and complicated work described above is required. To need
It is not suitable for products that are produced in high-mix low-volume production.

The object of claims 1, 2 and 3 is to provide an antireflection film on the molding surface of the mold to suppress reflection on the mold surface,
The mold and the mold in which the illuminance distribution before irradiating the lens blank and the mold is obtained in the resin layer without considering factors such as complicatedly repeated multiple reflections and attenuation due to transmission caused thereby This is to provide a method of molding the composite optical element used.

[0007]

According to a first aspect of the invention, an energy-curable resin is placed on the surface of a spherical glass optical substrate, and the energy-curable resin has a desired molding surface shape. in pressed, the mold for molding a composite optical element by irradiating energy, be deposited antireflection film on the entire surface of the molding surface of the mold
A mold for forming composite-type optical element characterized by being configured by. The invention of claim 2 is characterized in that the antireflection film adhered to the entire molding surface of the molding die is composed of two or more layers, and the molding die of the composite optical element according to claim 1. In the invention of claim 3, the energy curable resin is placed on the surface of the spherical glass optical substrate, and the energy curable resin has a desired molding surface shape and the entire molding surface. In the molding surface of the mold molding surface by pressing with a molding mold coated with an antireflection film, and by irradiating energy that allows the resin and the optical substrate having a desired thickness to pass through by the pressing . In the method for molding a composite optical element, the resin on the optical substrate is cured by suppressing the reflection of the pre-energy, and the composite optical element is molded.

[0008]

According to the functions of claims 1, 2 and 3, it is possible to suppress reflection on the molding surface of the mold by molding using a mold in which an antireflection film is applied to the entire molding surface. . Therefore, it is possible to supply the energy to the resin with the illuminance distribution set in the initial state as it is, without considering the complicated and repeatedly occurring multiple reflection elements that exist in the past.

[0009]

Embodiment 1 FIGS. 1 and 2 are schematic configuration diagrams showing this embodiment. Reference numeral 1 denotes a mold having an antireflection film 2 formed on its molding surface, and the mold 1 is held so as to be vertically movable. A lens holding member 5 is installed below the mold 1, a lens blank 3 is placed on the lens holding member 5, and an ultraviolet curable resin 4 is supplied to the upper surface of the lens blank 3. An ultraviolet irradiation lamp 6 is installed below the lens blank 3.

Generally, many lenses obtained by the replica molding method are aspherical lenses. That is, the molding surface of the mold used there has a pattern opposite to the desired surface shape of the lens. That is, when such an aspherical shape is to be obtained by the resin layer, the resin thickness is not the same in the radial direction.

When parallel light is irradiated to cure the resin layer as described above, the thin portion of the resin layer is solidified before the thick portion, and the desired surface shape cannot be obtained. . Therefore, normal ultraviolet rays are not parallel rays and are irradiated with an illuminance distribution proportional to the desired resin thickness distribution, but in the present embodiment, in order to simplify the description,
The mold 1 having the same radius of curvature as the molding surface of the lens blank 3 was used to make the resin thickness distribution obtained thereby uniform.

As the ultraviolet curable resin 4, a resin which is adjusted so that the polymerization is started at 360 nm is used, and the ultraviolet irradiation lamp 6 can irradiate light having a characteristic that a peak comes to 360 nm. ing. Therefore, the antireflection film 2 is composed of a single-layer MgF ₂ having a film thickness of 90 nm corresponding to λ / 4. And, of course, the lens blank 3 is formed with an antireflection film for ensuring its optical performance.

The operation of this embodiment will be described below. First,
The ultraviolet curable resin 4 is supplied to the lens blank 3 and the upper surface (molding surface side) by a dispenser (not shown), and is conveyed to the lens holding member 5. After that, mold 1 and lens blank 3
Are relatively close to each other, and the ultraviolet curable resin layer has a desired thickness. Then, the ultraviolet irradiation lamp 6 irradiates the resin layer with ultraviolet rays. After the polymerization is completed, the composite optical element 7 including the resin 4 and the lens blank 3 is peeled from the mold 1.

FIG. 2 shows a locus of light rays in the present invention using the mold 1 described above. According to this, the light emitted from the ultraviolet irradiation lamp 6 passes through the lens blank 3 and the resin layer and reaches the surface of the mold 1, but is almost not reflected by the antireflection film 2, so that the illuminance distribution in the resin layer is The same pattern as the distribution immediately before entering the blank 3 will be maintained. Needless to say, even if an illuminance distribution is provided, that distribution is maintained.

According to this embodiment, since the reflection on the surface of the mold can be almost suppressed by molding using the mold having the antireflection film on the surface thereof, it is possible to repeat the complex repetition. It is possible to obtain the illuminance distribution before irradiating the lens blank and the mold in the resin layer, without taking into consideration factors such as reflection and attenuation due to transmission generated thereby. In other words, the complicated work required to create the filter used in the conventional example is completely unnecessary. Furthermore, even if you have to replace the mold to mold different shapes, you do not have to create a filter each time,
You can move smoothly to the next molding.

[0016]

Embodiment 2 FIGS. 3 and 4 show this embodiment, FIG. 3 is an explanatory view of an antireflection film, and FIG. 4 is a graph. In this embodiment, the structure and film thickness of the antireflection film in the first embodiment are different, and the other structures have the same constituent parts, and the description thereof will be omitted.

In the present embodiment, the reflectance n = 1.52 of the ultraviolet curable resin, the absorptance k = 0, the reflectance n = of the mold surface.
1.95 and absorptance k = 3.53, Ta ₂ O ₅ optical film thickness nd = 72n from the first layer as shown in FIG.
m, MgF ₂ nd = 78 nm, Ta ₂ O ₅ nd = 8
6 nm, MgF ₂ nd = 52 nm, Ta ₂ O ₅ nd
By applying an antireflection film having a structure of = 10 nm on the mold surface, it is possible to obtain the reflection characteristics as shown in FIG.

According to the present embodiment, the reflectance can be made closer to zero than in the first embodiment, and the illuminance distribution before irradiating the lens blank and the mold can be more completely obtained in the resin layer. It will be possible.

[0019]

Third Embodiment FIGS. 5 and 6 show the present embodiment, FIG. 5 is an explanatory view of an antireflection film, and FIG. 6 is a graph. In this embodiment, the structure and film thickness of the antireflection film in the first embodiment are different, and the other structure is composed of the same constituent parts, and the description thereof is omitted.

In the present embodiment, the reflectance n = 1.52 of the ultraviolet curable resin, the absorptance k = 0, and the reflectance n = of the mold surface.
Assuming that the absorption rate is 1.95 and the absorptivity k = 3.53, as shown in FIG. 5, the TiO ₂ optical film thickness nd = 74n from the first layer.
m, SiO ₂ nd = 79 nm, TiO ₂ nd = 43
By applying an antireflection film having a structure of nm on the surface of the mold, it becomes possible to obtain the reflection characteristics as shown in FIG.

According to this embodiment, it is possible to obtain almost the same reflection characteristics with a film structure smaller than that of the second embodiment.

[0022]

Fourth Embodiment FIGS. 7 and 8 show the present embodiment, FIG. 7 is an explanatory view of an antireflection film, and FIG. 8 is a graph. In this embodiment, the structure and film thickness of the antireflection film in the first embodiment are different, and the other structure is composed of the same constituent parts, and the description thereof is omitted.

In this example, the reflectance n = 1.52 of the ultraviolet curable resin, the absorptance k = 0, and the reflectance n = of the mold surface.
1.95 and absorptance k = 3.53, as shown in FIG. 7, the first layer SiO ₂ optical film thickness nd = 100 nm,
By applying the antireflection film having the structure of the second layer Fe nd = 5 nm on the mold surface, it becomes possible to obtain the reflection characteristics as shown in FIG.

According to the present embodiment, the above-mentioned Embodiments 2 and 3 are used.
It is possible to obtain the best reflection characteristics with the smallest film configuration as compared with the above. Furthermore, because the design is designed to suppress the reflectance in a wider band, the peak is 360 nm.
It is possible to support a wide range of light sources, not limited to such light sources.

Needless to say, the film structure may be other than the above-mentioned embodiments as long as reflection can be prevented.

[0026]

The effects of the first, second and third aspects of the present invention are that the reflection on the molding surface of the mold can be suppressed by molding the antireflection film using a mold in which the entire molding surface is adhered. It is possible to obtain the illuminance distribution before irradiating the lens blank and the mold in the resin layer without taking into account factors such as complicatedly repeated multiple reflections and attenuation caused by the resulting transmission. To enable. In other words, the complicated work required to create the filter used in the conventional example is completely unnecessary. Further, even when the mold has to be replaced to mold a different shape, it is not necessary to make a filter each time, and the next molding can be smoothly performed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram illustrating a first embodiment.

FIG. 2 is a schematic configuration diagram showing a first embodiment.

FIG. 3 is an explanatory diagram showing a second embodiment.

FIG. 4 is a graph showing Example 2.

FIG. 5 is an explanatory diagram showing a third embodiment.

FIG. 6 is a graph showing Example 3.

FIG. 7 is an explanatory diagram showing a fourth embodiment.

FIG. 8 is a graph showing Example 4.

FIG. 9 is a graph showing Example 4.

FIG. 10 is a graph showing Example 4.

[Explanation of symbols]

1 mold 2 Antireflection film 3 lens blank 4 UV curable resin 5 Lens holding member 6 UV irradiation lamp 7 Composite optical element

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Claims (3)

(57) [Claims] 1. A composite is obtained by placing an energy curable resin on the surface of a spherical glass optical substrate, pressing the energy curable resin with a molding die having a desired molding surface shape, and irradiating with energy. A molding die for molding a mold optical element, which is constituted by depositing an antireflection film on the entire molding surface of the molding die. 2. The molding of a composite optical element according to claim 1, wherein the antireflection film deposited on the entire molding surface of the molding die comprises two or more layers. Mold. 3. An energy curable resin is placed on the surface of a spherical glass optical substrate, the energy curable resin has a desired molding surface shape, and an antireflection film is deposited on the entire molding surface. By pressing with a molding die, and by irradiating energy that allows the resin and the optical substrate having a desired thickness to pass through by the pressing , reflection of pre-energy on the molding surface of the mold molding surface is suppressed. A method for molding a composite-type optical element, comprising: curing a resin on the optical substrate to form a composite-type optical element.