JP4166845B2 - Glasses plastic lens with antireflection film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a spectacle plastic lens having an antireflection film, and in particular, in an eyeglass plastic lens in which an antireflection film having a highly evaluated film performance is applied using a sputtering method, occurrence of cracks in the antireflection film is caused. It relates to the structure that was prevented.
[0002]
[Prior art]
In recent years, plastics are frequently used in lenses for eyeglasses from the viewpoint of light weight and excellent impact resistance. In the spectacle plastic lens, an antireflection film is formed on both surfaces thereof. The antireflection film prevents surface reflection in the spectacle plastic lens. This is because when the surface reflection occurs, the transmittance of the optical system is lowered, an increase in light that does not contribute to image formation is caused, and the contrast of the image is lowered. Conventionally, an antireflection film for a spectacle plastic lens has been formed as a single layer film or a multilayer film mainly by a vacuum deposition method.
[0003]
[Problems to be solved by the invention]
Currently, a deposition method and apparatus are being proposed in which an antireflection film is formed on a spectacle plastic lens with a simple configuration using a sputtering method (or sputtering method) to improve productivity. This film forming apparatus includes a sputter film forming chamber in which a different thin film can be produced by exchanging a target in a vacuum vessel. In the sputter film forming chamber without exposing the spectacle plastic lens to the atmosphere, a multilayer film is formed on the lens surface. An antireflection film can be formed, and further, both surfaces of the lens can be formed simultaneously. According to this film forming apparatus, when a multilayer film is deposited on the surface of a spectacle plastic lens, a target corresponding to the material of each film is installed in the vacuum container, and the target is replaced to perform sputter film formation. Therefore, for example, by forming a film by alternately laminating two kinds of films of a high refractive index substance and a low refractive index substance, a multilayer antireflection film can be easily formed. By accurately controlling the thickness and the like of the film, an antireflection film having highly evaluated film performance can be formed.
[0004]
However, when a high-refractive-index material is formed as the first layer of an antireflection film on a plastic base material for eyeglasses, which is an organic substance, water absorption over time (moisture absorption) and stress balance at the interface due to external pressure can be achieved. This causes a problem that cracks are likely to occur in the antireflection film from the interface. For example, when a spectacle plastic lens formed with a multilayer antireflection film formed from a high refractive index material as the first layer is fitted into a spectacle frame with a very strong force and absorbed, the edge portion of the spectacle plastic lens May cause cracks.
[0005]
An object of the present invention is to solve the above-described problem, and in the case where a multilayered antireflection film is formed by applying a high refractive index material to the first layer on an organic plastic substrate for eyeglasses, the plastic An object of the present invention is to provide a spectacle plastic lens having an antireflection film in which the surface of a base material is modified to prevent generation of cracks.
[0006]
[Means and Actions for Solving the Problems]
In order to achieve the above object, a spectacle plastic lens having an antireflection film according to the present invention is configured as follows.
[0007]
First spectacle plastic lens (corresponding to claim 1): A spectacle plastic lens obtained by applying an antireflection film to a plastic base material by using a sputtering method. The antireflection film has a first layer on the plastic base material side. It is a multilayer film formed by alternately laminating these high refractive index materials and low refractive index materials, with a high refractive index material and the next layer as a low refractive index material. A hard film is coated, and an ultra-thin film for preventing cracks by SiO _(2-x) (x = 0, 1) as a pretreatment layer is formed on the hard film of the plastic substrate with a thickness of 15 angstroms or more and less than 50 angstroms. The film is formed with a thickness, and an ultrathin film is provided between the hard film and the antireflection film.
[0008]
In the above spectacle plastic lens, an ultra-thin film as a pretreatment layer is provided between the high refractive index film of the first layer of the multilayer antireflection film and the plastic substrate. Occurrence can be prevented.
[0010]
Second spectacle plastic lens (corresponding to claim 2 ): In the first spectacle plastic lens, preferably, the high refractive index material is any one of Zr, Ti, Ta, or an alloy of two or more thereof. The low-refractive-index substance is a metal oxide formed by sputtering using a Si target.
[0011]
Third spectacle plastic lens (corresponding to claim 3 ): In the second spectacle plastic lens, preferably, the target of the high refractive index material is configured to contain Si. Thereby, the high refractive index film is formed containing Si, and the hardness and durability of the film are improved.
[0012]
Fourth spectacle plastic lens (corresponding to claim 4 ): In the second spectacle plastic lens, preferably, a Si target is provided separately from the target of the high refractive index material during the film formation of the high refractive index material. Two types of targets were sputtered simultaneously to form a high refractive index material as a mixed film. Also in this case, Si is contained in the high refractive index film, so that the hardness of the film is improved.
[0013]
Fifth spectacle plastic lens (corresponding to claim 5 ): In the spectacle plastic lens described above, preferably, the antireflection film is a multilayer film of ten layers, and a sixth layer of a low refractive index substance film located in the middle The thickness was increased.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
[0015]
FIG. 1 is a schematic cross-sectional view showing an example of a film structure of an antireflection film, and shows one of the antireflection films formed on both surfaces of a spectacle plastic lens. The plastic substrate 10 shown in FIG. 1 is a substrate for a spectacle plastic lens. For example, CR-39 (diethylene glycol bisallyl carbonate polymer) is used as the material of the plastic substrate 10. The surface of the plastic substrate 10 is coated with a hard film 11 for the purpose of increasing the hardness of the surface. For example, a colloidal silica-containing organosilicon resin is used for the hard film 11, and the details of the composition are described in, for example, Japanese Patent Publication No. 4-55615. The plastic base material of the spectacle plastic lens usually has a curvature and a curved shape. However, in FIG. 1, it is shown in the form of a flat plate for convenience of explanation. When a plastic substrate is curved, the film deposited thereon generally curves along the substrate surface.
[0016]
On the plastic substrate 10, an antireflection film 13 having a multilayer structure is preferably formed by a sputtering film forming method. The antireflection film 13 is actually formed on the hard film 11. More specifically, an ultrathin film 12 of SiO _(2-x) (x = 0, 1) is formed between the hard film 11 and the antireflection film 13 as a pretreatment layer.
[0017]
First, the antireflection film 13 will be described. As shown in FIG. 1, the antireflection film 13 according to the present embodiment is configured as, for example, a 10-layer multilayer film. In this antireflection film 13, the lowermost film 131 located on the plastic substrate 10 side is a high refractive index film. Next, a low refractive index film 132 is formed on the high refractive index film 131. Thereafter, these films 133 to 140 are alternately and sequentially formed in the order of the high refractive index film and the low refractive index film. As a result, the first layer, the third layer, the fifth layer, the seventh layer, and the ninth layer 131, 133, 135, 137, and 139 become high refractive index films, and the second layer, the fourth layer, the sixth layer, The antireflection film 13 having a multilayer film structure is formed by laminating the layers 132, 134, 136, 138, and 140 as the low-refractive index films. The outside of the tenth low refractive index film 140 is the atmosphere.
[0018]
In the present embodiment, the high refractive index material forming the high refractive index film is, for example, a metal oxide ZrO ₂ of zirconium (Zr), and the low refractive index material forming the low refractive index film is, for example, silicon ( Si) is a metal oxide SiO ₂ . In addition, as the high refractive index substance, any metal oxide (TiO ₂ , Ta ₂ O ₅ or the like) of titanium (Ti) or tantalum (Ta) can be used. Furthermore, a metal oxide made of an alloy of two or more of zirconium (Zr), titanium (Ti), and tantalum (Ta) can be used as the high refractive index material. The high refractive index film and the low refractive index film described above are preferably fabricated using a sputtering method. For this reason, a target of a high refractive index material and a target of a low refractive index material are prepared.
The high refractive index film can also be formed as a mixed film containing the above high refractive index substance and Si. By including Si in the high refractive index film, the performance of the film such as hardness and durability can be improved. As a method for making such a mixed film, for example, two methods can be used. The first method is to include Si in the high refractive index target. By performing sputtering film formation using such a target, a high refractive index film containing Si can be deposited. The second method is to provide a Si target separately from the high refractive index material target. The high refractive index target and the Si target are simultaneously sputtered to form a mixed film. The Si target can be used in combination with a low refractive index target.
[0020]
In the antireflection film 13 having the multilayer structure formed as described above, the film thicknesses of the high refractive index film and the low refractive index film of each layer are preferably as follows when λ is 500 nm (nanometers): Is set.
[0021]
The film thickness of the high refractive index film of the first layer is included in the range of 0.075λ to 0.085λ,
The film thickness of the low refractive index film of the second layer is included in the range of 0.115λ to 0.130λ,
The film thickness of the high refractive index film of the third layer is included in the range of 0.177λ to 0.199λ,
The film thickness of the low refractive index film of the fourth layer is included in the range of 0.101λ to 0.114λ,
The film thickness of the high refractive index film of the fifth layer is included in the range of 0.102λ to 0.115λ,
The film thickness of the low refractive index film of the sixth layer is included in the range of 0.471λ to 0.511λ,
The film thickness of the high refractive index film of the seventh layer is included in the range of 0.102λ to 0.115λ,
The film thickness of the low refractive index film of the eighth layer is included in the range of 0.045λ to 0.060λ,
The film thickness of the high refractive index film of the ninth layer is included in the range of 0.270λ to 0.304λ,
The film thickness of the tenth low refractive index film is set so as to be included in the range of 0.244λ to 0.275λ. In the above, the most preferable film thickness value of each layer is the center value in each range.
[0022]
The above-described antireflection film 13 preferably has a total film thickness in the range of 4800 to 5800 angstroms, and more preferably has a total film thickness of the low refractive index film of 3500 angstroms or more. This is to ensure the hardness required for the antireflection film, durability such as wear resistance, adhesion as a film, and the like. In the case of the present embodiment, in particular, the film thickness of the sixth layer low-refractive index film 136 located in the intermediate region is made relatively thick compared to other films, thereby the antireflection film 13. The required film thickness is achieved and the required conditions such as hardness and durability are satisfied. The reason why the film located in the middle among the plurality of low refractive index films is relatively thick is based on the reason that such a structure is suitable in view of the stress of the film.
[0023]
The number of layers of the antireflection film 13 having a multilayer structure is not limited to the above ten layers. The number of antireflection films having a multilayer film structure is preferably as small as possible from the viewpoint of film productivity, but can be arbitrarily determined in relation to required film performance.
[0024]
Further, as described above, a plastic base material of a normal spectacle plastic lens has a curvature and a curved shape. When the antireflection film 13 having the multilayer film structure shown in FIG. 1 is produced by using a sputtering method on a curved plastic substrate, the film thickness distribution difference depends on the curvature of each part of the plastic substrate. Interference color unevenness due to this, and interference color change due to oblique incidence occur. Therefore, in order to reduce such a problem, it is preferable that the above-described antireflection film 13 is designed as a film having broadband characteristics.
[0025]
When applying the antireflection film 13 having the above multilayer film structure to the plastic substrate 10, as described above, the ultrathin film 12 of SiO _{2 (2-x)} is formed as the pretreatment layer. The film thickness of the ultrathin film 12 is preferably in the range of 15 to 50 angstroms. By applying such an ultra-thin film 12 as a pretreatment layer, the stress balance between the interface of the plastic substrate 10 and the high refractive index film 131 is changed appropriately, and as a result, moisture resistance and pressurization are caused. It is possible to prevent the occurrence of cracks in the antireflection film 13 and maintain good appearance as a spectacle plastic lens. As a matter of course, the adhesion between the antireflection film 13 and the plastic substrate 10 can be kept high. In addition, when the film thickness of the ultrathin film 12 exceeds 50 angstroms, there arises a problem that the adhesiveness is lowered.
[0026]
Next, referring to FIG. 2, the antireflection film (A) having the above-described configuration is compared with two examples of antireflection films (B) and (C) having other configurations. In FIG. 2A, the antireflection film 13 having a multilayer structure is composed of 10 layers of a high refractive index film and a low refractive index film. The numbers 1 to 10 at the left end of the antireflection film 13 indicate layer numbers. The thicknesses of the respective layers from the high refractive index film of the first layer to the low refractive index film of the tenth layer are 0.08λ, 0.12λ, 0.19λ, 0.11λ, and 0.11λ as shown in the drawing. 0.49λ, 0.11λ, 0.05λ, 0.29λ, and 0.26λ. These film thicknesses are included in the range of the film thickness of each layer described above. The above-described structure of the antireflection film 13 is the same also in each of the antireflection films of FIGS.
[0027]
In the configuration shown in FIG. 2A, the antireflection film 13 is formed on a plastic substrate 10 having a hard film 11 coated on the surface thereof, and a SiO _{2 (2-x)} film having a thickness of 15 Å (Å). The film is formed through the thin film 12. That is, the SiO _{2 (2-x)} ultrathin film 12 is applied as a pretreatment. The upper side of the low refractive index film of the tenth layer is the atmosphere.
[0028]
In contrast to the above, in the configuration of FIG. 2B, a thin film 12a made of SiO _{2 (2-x)} is similarly formed between the antireflection film 13 and the plastic substrate 10 having the surface coated with the hard film 11. It is given as a pretreatment. However, in this example, the thickness of the thin film 12a is 80 angstroms, which is larger than 50 angstroms, and is not included in the above-mentioned range.
[0029]
Further, in the configuration of FIG. 2C, a thin film of SiO _{2 (2-x)} is not applied between the antireflection film 13 and the plastic base material 10 whose surface is coated with the hard film 11. That is, no pretreatment with the ultrathin film is performed. The antireflection film 13 is formed directly on the plastic substrate 10 coated with the hard film 11.
[0030]
Next, the film performance of each spectacle plastic lens having the configuration shown in FIGS. 2A, 2B, and 2C will be compared. In this comparison, eyeglass plastic lenses having the respective configurations shown in FIGS. 2A, 2B, and 2C were produced, and these eyeglass plastic lenses were fitted into the eyeglass frame, and the humidity was 90% and the temperature. After being left in a constant temperature and humidity oven at 40 ° C. for 24 hours, the adhesion of the antireflection film and the appearance of the spectacle plastic lens (the presence or absence of cracks) were examined. For "adhesion", the surface of a spectacle plastic lens having an antireflection film is cross-cut at 100 intervals at 1 mm intervals, and after strongly applying cellophane tape, it is peeled off rapidly to examine whether the antireflection film is peeled off. It is evaluated by.
[0031]
As a result, in the spectacle plastic lens having the configuration shown in FIG. 2A, the adhesion was 100/100, no peeling was observed, and no change in appearance was observed. In the spectacle plastic lens having the configuration shown in FIG. 2B, the adhesiveness was 0/100 and all peeled off, and the performance was extremely poor. However, there was no change in appearance. In the eyeglass plastic lens having the configuration of FIG. 2C, the adhesiveness was 100/100, which was good. However, the appearance was problematic in that cracks occurred from the edge of the lens.
[0032]
As is clear from the above comparison, the antireflection film 13 provided with the ultra-thin film 12 as the pretreatment in the eyeglass plastic lens (plastic base material 10) has high film performance in terms of adhesion and appearance. is there. In addition, this antireflection film 13 exhibits excellent film performance in terms of abrasion resistance, alkali resistance, heat resistance, acid resistance, and artificial sweat resistance.
[0033]
Further, in the spectral reflectance curve of the antireflection film described above, a low reflectance is achieved in a wide wavelength range of about 420 to 740 nm, and a broadband antireflection film is realized. In particular, the reflectance is relatively high in the wavelength range of about 480 to 550 nm.
[0034]
Further, in the above-described ultrathin film and antireflection film, the interference wavelength is set by setting the main wavelength range to 480 to 550 nm, the stimulation purity range to 10 to 30%, and the luminous reflectance to 0.7 to 1.8%. Is green. Here, the “main wavelength” is an element representing chromaticity by monochromatic display, and a wavelength corresponding to a point where a line connecting a light source and a point represented by chromaticity coordinates on the chromaticity diagram intersects a spectrum locus. In other words, “stimulus purity” indicates how close the point of the main wavelength is to the light point from 0 to the spectrum locus, and the closer the point, the brighter the color. When displaying the color of a reflective object, the luminous reflectance and chromaticity are generally used. Furthermore, when the chromaticity is displayed in a single color, the above main wavelength and stimulation purity are used. The luminous reflectance is represented by the ratio of the light beam reflected from the object and the light beam incident on the object.
[0035]
【The invention's effect】
As is apparent from the above description, according to the present invention, when a multilayer antireflection film having a high refractive index film as a first layer is applied to a spectacle plastic lens or the like by sputtering, SiO _{2 (2- Since} the ultrathin film _x) is applied, generation of cracks in the antireflection film can be prevented, and the appearance as a spectacle plastic lens can be improved. In addition, a green interference color can be stably obtained with an ultra-thin film or the like, and a commercially valuable eyeglass plastic lens excellent in eye physiology and aesthetics can be produced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the structure of a spectacle plastic lens according to the present invention having a multilayer antireflection film.
FIG. 2 shows a pre-treated spectacle plastic lens (A) according to the present invention, a spectacle plastic lens (B) having a pre-treatment layer having a film thickness outside a predetermined range, and an untreated spectacle plastic lens (C). Is a cross-sectional view for comparison.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Plastic base material 11 Hard film | membrane 12 Ultra-thin film 13 as a pre-processing layer Antireflection film

Claims (5)

It is a spectacle plastic lens formed by applying an antireflection film to a plastic substrate using a sputtering method,
The antireflective film is formed by alternately stacking a high refractive index material and a low refractive index material with the first layer on the plastic substrate side as a high refractive index material and the next layer as a low refractive index material. A multilayer film formed,
The surface of the plastic substrate is coated with a hard film,
On the hard film of the plastic substrate, an ultra-thin film for preventing cracking by SiO _{2 (2-x)} (x = 0, 1) is formed as a pretreatment layer with a film thickness of 15 angstroms or more and less than 50 angstroms, The ultrathin film is provided between a hard film and the antireflection film,
An eyeglass plastic lens having an antireflection film.   The high refractive index substance is a metal oxide formed by sputtering using a target made of Zr, Ti, Ta, or an alloy of two or more of these, and the low refractive index substance is 2. The eyeglass plastic lens having an antireflection film according to claim 1, wherein the spectacle plastic lens is a metal oxide formed by sputtering using a Si target.   The spectacle plastic lens according to claim 2, wherein the target of the high refractive index material contains Si.   When forming the high refractive index material, a Si target different from the target of the high refractive index material was provided, and two types of the targets were simultaneously sputtered to form the high refractive index material as a mixed film. The spectacle plastic lens according to claim 2.   3. The glasses having an antireflection film according to claim 1, wherein the antireflection film is a multilayer film of 10 layers, and the film thickness of the low refractive index material of the sixth layer located in the middle is increased. Plastic lens.

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