JP2023175286A - Film formation method of lens and protection film-attached lens - Google Patents

Abstract

[Problem] To generate a highly homogeneous protective film, ensure the necessary protection function for the lens base, and generate good ghost and flare that can be used for rendering effects. [Solution] The refractive index of the lens base 2 is in the range of 1.40-2.10, the refractive index of the coating material C is in the range of 1.20-2.50, and the lens base 2 itself has a refractive index of 1.40-2.10. Brightness conditions such that the difference Md between the first reflectance Mf and the second reflectance Ms when the lens base 2 is coated with 3 m of film-formed layer of coating material C is 9.50% or less in a predetermined light wavelength range. XL and the first chroma Sf of the lens base 2 itself in the L*a*b* color space when irradiated with light R from a D65 standard light source and the film formed layer of the coating material C on this lens base 2. A protective film 3 is provided that satisfies the saturation condition XS such that the difference Sd in the second saturation Ss is 2.70 or less. [Selection diagram] Figure 1

Description

The present invention relates to a lens film forming method suitable for use in providing a protective film on the surface of the lens itself, and a lens with a protective film provided with the protective film.

Generally, when taking pictures with a camera, there is a problem that strong light from the sun or ceiling lights appears in the image as unnecessary ghosts and flares. By applying a multilayer anti-reflection coating, unnecessary reflected light that causes ghost and flare is reduced.

Conventionally, lenses with such an antireflection film include an interchangeable lens having an antireflection film described in Patent Document 1, an antireflection plastic lens described in Patent Document 2, and an antireflection plastic lens described in Patent Document 3. Synthetic resin lenses having an antireflection layer are known. The interchangeable lens having an antireflection film disclosed in Patent Document 1 has excellent transmittance characteristics in medium refractive index glass, has little occurrence of flare or ghosting, and has a uniform lens with excellent scratch resistance and anti-fading effect. The purpose is to provide an interchangeable lens having an anti-reflection film, and specifically, an anti-reflection film formed by laminating first to third layers on a base material from the base material side, The base material has a refractive index of 1.53 or more and less than 1.60 for light in a wavelength range of 400 to 700 nm, and the first layer is a dense layer containing alumina as a main component and having an optical thickness of 25.0 to 250.0 nm. The second layer is a dense layer with a refractive index of 1.40 to 1.50 and an optical thickness of 100.0 to 145.0 nm, and the third layer is composed of an aggregate of mesoporous silica nanoparticles and has a refractive index of 1.12. ~1.20 nm, and an optical film thickness of 100.0 to 138.5 nm (the optical film thickness in Document 1 is refractive index x physical film thickness).

In addition, the anti-reflective plastic lens of Patent Document 2 is thin, lightweight, has a high refractive index, has no visible interference fringes on the coating film, has no unevenness or variation in reflected color, and has a high-performance anti-reflective coating with low reflectance. Specifically, the objective is to provide a plastic lens made of a polymer of an aromatic compound of a predetermined formula and an isothiocyanate compound, and an organosilicon compound of a predetermined formula or a hydrolyzate thereof. , and an organosilicon coating film consisting of a cured film of one or more oxide sols such as antimony pentoxide sol, and a multilayer antireflection film containing titanium and silicon oxides on this film. .

Further, the synthetic resin lens of Patent Document 3 has a coating layer on the surface, and the lens surface is coated with a hard coat obtained from a coating composition consisting of a modified melamine resin composition and an isothiocyanate compound. A multilayer anti-reflection film made of a metal oxide is formed on the hard coat film.

Japanese Patent Application Publication No. 2010-55060 Japanese Patent Application Publication No. 9-5501 Japanese Unexamined Patent Publication No. 153601/1983

However, the above-mentioned conventional lenses provided with an antireflection film also have the following problems.

That is, when photographing with a camera, there are cases in which ghost and flare are intentionally used to enhance the depiction effect. This can be achieved by using an uncoated lens, but since the anti-reflection film described above also has the function of protecting the lens by preventing deterioration and deterioration of the lens itself, with an uncoated lens, A problem arises in that these functions cannot be secured.

On the other hand, by appropriately setting the thickness of the anti-reflection film, more specifically, by setting it thinner, it is possible to ensure the necessary protection function for the lens and to generate a certain amount of ghost and flare that can ensure the rendering effect. If this could be done, it would be possible to obtain a more desirable lens with a protective film, but the reality is that no suitable lens with a protective film having such a function has been provided so far.

In particular, when the film thickness is set to a certain degree, it is relatively easy to form a homogeneous coating layer with little variation, but when the film thickness is thin and the film is almost uncoated For example, the film formation process (film formation control) for producing a highly homogeneous protective film is not easy, as it is necessary to extremely shorten the film formation time.

The object of the present invention is to provide a lens film forming method and a lens with a protective film that solve the problems existing in the background art.

In the method for forming a lens film according to the present invention, when providing a protective film 3 of a predetermined coating material C on a lens surface 2f of a lens base 2, a lens base 2 having a refractive index selected from a range of 1.40 to 2.10 is used. and the refractive index of the coating material C is selected from the range of 1.20-2.50, and the first reflectance Mf of the lens base 2 itself and the coating layer 3 m of the coating material C on the lens base 2 are selected. By measuring the second reflectance Ms in a state where and the first chroma Sf of the lens base 2 itself in the L*a*b* color space when irradiated with light R from a D65 standard light source and the film formation layer 3m of the coating material C on this lens base 2. By measuring the second chroma Ss in a state where It is characterized in that the protective film 3 is provided by performing film treatment.

Further, in the lens 1 with a protective film according to the present invention, when forming a lens with a protective film in which a protective film 3 of a predetermined coating material C is provided on the lens surface 2f of the lens base 2 which has not been formed, the refraction of the lens base 2 is index is in the range of 1.40-2.10, and the refractive index of the coating material C is in the range of 1.20-2.50, and the first reflectance Mf of the lens group 2 itself and this lens group 2 satisfies the brightness condition XL in which the difference Md in the second reflectance Ms is 9.50 [%] or less in the predetermined light wavelength range, and from a D65 standard light source when a 3 m film-formed layer of coating material C is provided on the The first chroma Sf of the lens base 2 itself in the L*a*b* color space when irradiated with the light R of It is characterized by being provided with a protective film 3 that satisfies the saturation condition XS such that the difference Sd in degrees Ss is 2.70 or less.

On the other hand, according to a preferred embodiment of the present invention, 380-780 [nm] can be applied to the predetermined light wavelength range. In addition, when implementing the film forming method, the reflectance Mf, Ms for the incident light R perpendicular to the lens surface 2f can be used for the brightness condition XL, and the reflectance Mf, Ms for the incident light R perpendicular to the lens surface 2f can be used for the saturation condition XS. On the other hand, the reflected light of the light R that is perpendicularly incident can be used as the measurement light Rm. Furthermore, when calculating the difference Sd between the first saturation Sf and the second saturation Ss under the saturation condition XS, the difference between a* (a star) and b* (b star) in the L*a*b* color space is can be used. In addition, in the film forming process of the coating material C, at least one layer (3 ma) can be provided as a film forming layer 3m. At this time, when providing two or more 3 m film layers (3 ma, 3 mb...), the film layer (3 mb...) may be added on the condition that the entire 3 m satisfies the brightness condition XL and the saturation condition XS. can. Moreover, the coating material C can contain an optical film material.

According to the method for forming a lens film and the lens 1 with a protective film according to the present invention, the following remarkable effects are achieved.

(1) When implementing the film-forming method, the thickness of the film-forming layer 3m to be generated can be created using the brightness condition XL and the saturation condition XS, so the film-forming process (forming In addition, it is possible to provide a protective film 3 that is close to a state without coating, such as easy film control), and it is also possible to generate a highly homogeneous protective film 3.

(2) By using the film forming method according to the present invention, in addition to ensuring the necessary protection function for the target lens 1 with a protective film, that is, the lens base 2, good ghost and flare that can be used for depiction effects can be obtained. It is possible to obtain a lens 1 with a protective film that can be generated.

(3) If 380-780 [nm] is applied to a predetermined light wavelength range according to a preferred embodiment, the entire visible light range can be covered, which is required for camera photography using a lens. Optical performance can be ensured.

(4) According to a preferred embodiment, when implementing the film forming method, if the reflectances Mf and Ms for the incident light R perpendicular to the lens surface 2f are used as the brightness condition XL, accurate settings related to reflectance measurement, etc. can be achieved. Since this can be easily performed, it can contribute to improving the ease and accuracy of the film forming process, as well as lower cost and speed.

(5) According to a preferred embodiment, when implementing the film forming method, if the reflected light of the light R incident perpendicularly to the lens surface 2f is used as the measurement light Rm for the saturation condition XS, the accuracy regarding the saturation measurement can be improved. Since the settings and the like can be easily performed, it can contribute to improving the ease and accuracy of the film forming process, as well as lower cost and speed.

(6) According to a preferred embodiment, when obtaining the saturation condition XS, if the difference between a* and b* in the L*a*b* color space is used, L* (L star) related to brightness can be calculated as the reflectance Since it can be obtained by a separate brightness condition XL using Mf and Ms, the saturation condition XS can be easily set only by the difference between a* and b*.

(7) According to a preferred embodiment, in the film forming process of the coating material C, at least one (3 ma) film forming layer 3 m can be provided. In other words, since 3 m of deposited layers can be added on the condition that the brightness condition XL and the saturation condition XS are satisfied, the total layer thickness of the deposited layers of 3 m can be reduced by providing two or more layers (3a, 3b...) if necessary. Optimization can be achieved from the viewpoint of setting.

(8) By including an optical film material in the coating material C according to a preferred embodiment, it is possible to use a known optical film material that has been widely used in the past, so it can be implemented easily and at low cost.

A flowchart for explaining the processing procedure of a film forming method according to a preferred embodiment of the present invention, A sectional view showing a part of a lens with a protective film according to a preferred embodiment of the present invention, An explanatory diagram for measuring reflectance and chroma used in the film forming method according to the embodiment, A characteristic diagram of optical film thickness versus light amount for explaining the measurement principle of the film forming method according to the embodiment, A list of characteristics of the lens base and coating material used in the film forming method according to the embodiment, A data table of the film structure of the lens with a protective film according to Example 1 of the embodiment, A data table of the measurement results of the lens with a protective film according to Example 1, A change characteristic diagram showing the reflectance in the light wavelength range with the measurement angle of the lens with a protective film according to Example 1 as a parameter, A characteristic diagram of saturation using a* (a star) and b* (b star) with the measurement angle of the lens with a protective film according to Example 1 as a parameter, A data table of the film structure of the lens with a protective film according to Example 2, A data table of the measurement results of the lens with a protective film according to Example 2, A change characteristic diagram showing the reflectance in the light wavelength range with the measurement angle of the lens with a protective film according to Example 2 as a parameter, A characteristic diagram of saturation using a* and b* with the measurement angle of the lens with a protective film according to Example 2 as a parameter, A data table of the film structure of the lens with a protective film according to Example 3, A data table of the measurement results of the lens with a protective film according to Example 3, A change characteristic diagram showing the reflectance in the light wavelength range with the measurement angle of the lens with a protective film according to Example 3 as a parameter, A characteristic diagram of saturation using a* and b* with the measurement angle of the lens with a protective film according to Example 3 as a parameter, A data table of the film structure of the lens with a protective film according to Reference Example 1, A data table of the measurement results of the lens with a protective film according to Reference Example 1, A change characteristic diagram showing the reflectance in the light wavelength range with the brightness of the lens with a protective film according to Reference Example 1 as a parameter, A characteristic diagram of saturation using a* and b* with the brightness of the lens with a protective film according to Reference Example 1 as a parameter, A data table of the film structure of the lens with a protective film according to Reference Example 2, A data table of the measurement results of the lens with a protective film according to Reference Example 2, A change characteristic diagram showing the reflectance in the light wavelength range with the saturation of the lens with a protective film according to Reference Example 2 as a parameter, A characteristic diagram of saturation using a* and b* with the saturation of the lens with a protective film according to Reference Example 2 as a parameter,

Next, preferred embodiments of the present invention will be described in detail based on the drawings.

First, the basic concept of the protective film-equipped lens 1 according to the same embodiment will be explained with reference to FIGS. 2 to 5 and FIG. 9.

FIG. 2 shows a partially extracted cross-sectional view of the protective film-equipped lens 1 according to the present embodiment. The lens 1 with a protective film can be obtained by forming a protective film 3 of a predetermined coating material C on the lens surface 2f of the lens base 2. Note that the lens base 2 in this specification means the lens itself in an unformed state without the protective film 3, that is, the film formation layer 3m. 2(a) shows a lens 1 with a protective film provided with a single layer 3ma as the protective film 3 (layer 3m), and FIG. 2(b) shows a lens 1 with a protective film 3 (layer 3m). 3m) shows a lens 1 with a protective film provided with two film formation layers 3ma and 3mb.

In this manner, when forming the film formation layer 3m by the film formation process using the coating material C, at least one film formation layer 3ma can be provided. That is, the film formation layer 3m may be a single film formation layer 3ma, or may be composed of two or more film formation layers (3ma.3mb...). Therefore, it is possible to add a film formation layer of 3m on the condition that the brightness condition XL and the saturation condition XS, which will be described later, are satisfied. Optimization can be achieved from the viewpoint of setting the overall layer thickness.

By the way, the lens 1 with a protective film according to the present embodiment prevents deterioration and deterioration of the lens base 2 by providing a thin film layer close to that of an unformed film (uncoated), and also allows the lens base 2 to be depicted as if there is no coating. This makes it possible to take pictures. In this case, this can be achieved by making the layer thickness of the deposited layer 3m as thin as possible, but as mentioned above, when creating the deposited layer 3m, there is a problem that it becomes difficult to control the film thickness. .

Therefore, in this embodiment, a predetermined setting range is provided in which the difference between the refractive index of the lens base 2 and the refractive index of the coating material C becomes small when performing the coating process, that is, the film forming process. In other words, the smaller the difference between the refractive index of the lens base 2 and the refractive index of the coating material C, the smaller the difference in reflectance (first reflectance Mf and second reflectance Ms) before and after the film formation layer 3m is provided. Md can be reduced. Therefore, it is desirable that the refractive index of the lens base 2 is selected from the range of 1.40-2.10, and the refractive index of the coating material C is preferably selected from the range of 1.20-2.50. desirable.

Furthermore, the brightness of the reflected light Rm was used as an index indicating the film formation state during the film formation process. Specifically, this first reflectance is determined by using the first reflectance Mf of the lens base 2 itself and the second reflectance Ms when the lens base 2 is coated with the coating layer 3m of the coating material C. A condition was set such that the difference Md between Mf and the second reflectance Ms was "9.50 [%] or less" in a predetermined light wavelength range. Therefore, if this difference Md exceeds 9.50 [%], the brightness of the ghost flare will be brighter or darker than the uncoated lens base 2, making it difficult to obtain a good ghost flare. I can't.

Therefore, the "brightness condition XL" requires that the difference Md between the first reflectance Mf and the second reflectance Ms be 9.50 [%] or less. In order to satisfy the brightness condition XL of 9.50% or less, it is necessary to select the refractive index of the lens base 2 itself from the range of 1.40 to 2.10, and also the refractive index of the coating material C. As the index increases, the reflectance increases, so the refractive index of the coating material C may be selected from the range of 1.20 to 2.50. In this way, the selection (designation) of the refractive index of the coating material C is the same as the designation of the brightness.

Note that the predetermined light wavelength range was set to 380-780 [nm]. In this way, by applying 380-780 [nm] as the predetermined light wavelength range, it is possible to cover the entire visible light range, ensuring the optical performance required for camera photography using lenses, etc. can be secured.

Furthermore, as shown in FIG. 3, the reflectances Mf and Ms of the incident light R perpendicular to the lens surface 2f were used for the brightness condition XL. As a result, accurate settings related to reflectance measurement can be easily performed, which can contribute to improving ease and accuracy, as well as cost reduction and speed, related to film formation processing.

In this case, to control the film thickness during the film forming process, a flat plate made of a glass material with a refractive index nd of 1.523 (thickness: 1.35 [mm]) is also formed, and the light R was perpendicularly incident, and the control was performed by measuring the magnitude of the reflectance Ms related to the reflected light Rm. Note that the reflected light Rm measured at this time has a specific wavelength (monitoring wavelength described later) obtained by filtering the reflected light. Furthermore, the reflectance of this flat plate before the film forming process was amplified and used. In the following description, the amplified reflectance will be referred to as the "light amount" and the light amount before the film forming process will be referred to as the "initial light amount."

The reason for amplifying the reflectance is as follows. In the case of a flat plate with no film formed, the reflectance is about 8%. Therefore, in the illustrated case, amplification of about 2.5 times was performed. As shown in FIG. 4, when setting the initial light amount, the larger the initial light amount, the greater the change in the light amount. That is, as shown in the characteristic line P1 shown in FIG. 4, if the initial light amount is too small, the change in light amount will also be small; on the other hand, if the initial light amount is too large, as shown in the characteristic line P3, the maximum light amount will be It exceeds 100%. Therefore, as shown in the characteristic line P2, it is desirable to set the maximum light amount to a large value that does not exceed 100%, and in this embodiment, it is set to about 2.5 times, which is considered appropriate.

In addition, in the film formation process, regarding control during the film formation process and the timing to end the film formation process, it is easier to control the wavelength portion (monitoring wavelength) where the change in light intensity is larger, so it is easier to control the initial light intensity setting and the monitoring wavelength. The size was set as shown in FIG.

On the other hand, regarding the color, the first chroma Sf of the lens base 2 itself and the composition of the coating material C on this lens base 2 in the L*a*b* color space when irradiated with light R from a D65 standard light source. The second chroma Ss with the film layer 3m provided was used, and the conditions were set such that the difference Sd between the first chroma Sf and the second chroma Ss was 2.70 or less. Therefore, satisfying this condition of "2.70 or less" is the "saturation condition XS". Note that if this difference Sd exceeds 2.70, the color tone (saturation) of the ghost/flare will be different from that of the lens base 2 on which no film is formed, making it impossible to obtain a good ghost/flare.

In this case, for the saturation condition XS, as shown in FIG. 3, the reflected light of the light R that is perpendicularly incident on the lens surface 2f is used as the measurement light Rm. As a result, accurate settings related to chroma measurement can be easily performed, which contributes to improvements in ease and accuracy, as well as low cost and speed, related to film formation processing.

Furthermore, when calculating the difference Sd between the first saturation Sf and the second saturation Ss of the saturation condition XS, the difference between a* and b* in the L*a*b* color space is calculated as shown in FIG. Using. In this case, since L* (L star) indicating brightness is obtained by a separate brightness condition XL using reflectance, the saturation condition XS can be easily set only by the difference between a* and b*. I can do it. Note that the difference Sd between the first saturation Sf and the second saturation Ss, which is set by the saturation condition XS, can be determined by the equation [Equation 1].

As described above, the brightness condition XL of 9.50 [%] or less and the saturation condition XS of 2.70 or less can be determined experimentally, and the settings are made to satisfy each of these conditions. Then, the range of the refractive index of the lens base 2 from 1.40 to 2.10 and the range of the refractive index of the coating material C from 1.20 to 2.50 can be determined.

FIG. 5 shows a list of characteristics of the lens base 2 and coating material C in the protective film-equipped lens 1 according to this embodiment. For the lens base 2, different types of glass materials are used, in particular glass materials A (nd: 1.81), glass materials B (nd: 1.88), and glass materials C (nd: 1.58) having different refractive indexes, These samples were designated as samples E1, E2, and E3, respectively. As the coating material C, LaTiO3 (lanthanum titanate (nd: 2.00)) was used for samples E1 and E2, and Al2O3 (aluminum oxide (nd: 1.63)) was used for sample E3. It was used. The coating materials C are all known as optical film materials Cm, but are not limited to such optical film materials Cm. Various coating materials C, such as MgF2 (fluorinated Various coating materials C such as magnesium (nd: 1.37) can be applied. Note that if the optical film material Cm is used as the coating material C, a known optical film material that has been widely used in the past can be used, so there is an advantage that it can be implemented easily and at low cost. Additionally, in FIG. 5, νd indicates the Abbe number of the lens group 2.

Therefore, in all of the samples E1 to E3 shown in FIG. When selecting the material, it is possible to select from samples E1 to E3.

Next, based on the concept of the lens 1 with a protective film according to the present embodiment, the results of verifying the effectiveness of the lens 1 with a protective film (and film forming method) according to the present embodiment will be described with reference to FIGS. 6 to 25. I will explain.

In FIGS. 6 to 25, the verification results of Example 1-3 that satisfied the brightness condition XL and the saturation condition XS of the lens with a protective film obtained by the film formation process according to the film formation method according to the present embodiment are shown. , and verification of Reference Example 1-2, including cases where the brightness condition XL or the chroma condition XS of the lens with a protective film obtained by the film formation process using the same film formation method is not satisfied as shown in FIGS. 6 to 17. The results are shown in FIGS. 18-25.

The verification results of Example 1 are shown in FIGS. 6-9. FIG. 6 shows the film structure of the protective film-equipped lens 1 according to Example 1. Example 1 used sample E1 shown in FIG. 5, in which glass material A was used for lens base 2 and lanthanum titanate was used for coating material C. As described above, both the lens base 2 and the coating material C satisfy the refractive index conditions required for the protective film-equipped lens 1. Further, the initial light amount was set to 20 [%], and the light wavelength monitored for control (monitoring wavelength) was 500 [nm]. Note that the number of layers is one.

FIG. 7 shows the data of the measurement results of the lens 1 with a protective film of Example 1, and FIG. 8 shows the measurement angle θ (0 [°], 10 [°], 20 [°]) are shown as parameters. In FIG. 8, D indicates a measurement position located at the center of the spherical surface on which the film of the lens base 2 is formed, and the measurement angle θ indicates an inclination centered on the measurement position D from the optical axis Fc.

As is clear from FIGS. 7 and 8, the maximum value of the difference Md between the reflectances Mf and Ms is 9.35 [%] when the measurement angle is 0 [°] and 9.35 [%] when the measurement angle is 10 [°]. .35 [%], and 9.30 [%] when the measurement angle was 20 [°], satisfying the brightness condition XL (9.50 [%] or less) at any angle.

Further, FIG. 9 shows a characteristic diagram of saturation using a* and b* with the measurement angle θ of the protective film-equipped lens 1 according to Example 1 as a parameter. As is clear from FIGS. 7 and 9, the difference Sd between the saturations Sf and Ss is 1.13 when the measurement angle is 0 [°], 1.22 when the measurement angle is 10 [°], and 1.22 when the measurement angle is 20 [°]. It becomes 1.58 at [°], and satisfies the saturation condition XS (2.70 or less) at any angle. In this way, Example 1 satisfies all the conditions required for the protective film-equipped lens 1 according to the present invention.

The verification results of Example 2 are shown in FIGS. 10 to 13. FIG. 10 shows the film structure of the protective film-equipped lens 1 according to the second embodiment. Example 2 used sample E2 shown in FIG. 5, in which glass material B having a slightly high refractive index was used for lens base 2, and lanthanum titanate was used for coating material C. As described above, both the lens base 2 and the coating material C satisfy the refractive index conditions required for the protective film-equipped lens 1. Note that the initial light amount, monitoring wavelength, and number of layers are the same as in Example 1.

FIG. 11 shows the data of the measurement results of the lens 1 with a protective film according to Example 2, and FIG. 12 shows the measurement angle θ( 0 [°], 10 [°], 20 [°], 30 [°]) are shown as parameters. As is clear from FIGS. 11 and 12, the maximum value of the difference Md between the reflectances Mf and Ms is 6.86 [%] when the measurement angle is 0 [°], and 6.86 [%] when the measurement angle is 10 [°]. .67 [%], 6.98 [%] when the measurement angle is 20 [°], and 7.13 [%] when the measurement angle is 30 [°], all under brightness condition XL (9.50 [%]). %] or less).

Further, FIG. 13 shows a characteristic diagram of saturation using a* and b* with the measurement angle θ of the protective film-equipped lens 1 according to Example 2 as a parameter. As is clear from FIGS. 11 and 13, the difference Sd between the saturations Sf and Ss is 0.88 when the measurement angle is 0 [°], 1.16 when the measurement angle is 10 [°], and 1.16 when the measurement angle is 20 [°]. [°], it becomes 1.51, and when the measurement angle is 30 [°], it becomes 2.47, both of which satisfy the saturation condition XS (2.70 or less).

In this way, Example 2 also satisfies all the conditions required for the protective film-equipped lens 1 according to the present invention. Sample E2 of Example 2 has a verification result that corresponds to the refractive index condition for selecting lens base 2, that is, near the maximum value of 1.40-2.10.

The verification results of Example 3 are shown in FIGS. 14-17. FIG. 14 shows the film structure of the protective film-equipped lens 1 according to Example 3. Example 3 uses sample E3 shown in FIG. 5, in which glass material C, which has the lowest refractive index among the examples, was used for lens base 2, and alumina was used for coating material C. As described above, both the lens base 2 and the coating material C satisfy the refractive index conditions required for the protective film-equipped lens 1. Further, the initial light amount was set to 60 [%], and the monitoring wavelength was 480 [nm]. Note that the number of layers is one.

FIG. 15 shows the data of the measurement results of the lens 1 with a protective film according to Example 3, and FIG. 16 shows the measurement angle θ( 0 [°], 10 [°], 20 [°], 29 [°]) are shown as parameters. As is clear from FIGS. 15 and 16, the maximum value of the reflectance difference Md is 1.45 [%] when the measurement angle is 0 [°] and 1.36 [%] when the measurement angle is 10 [°]. %], 1.29 [%] when the measurement angle is 20 [°], and 1.56 [%] when the measurement angle is 29 [°], both of which are under brightness condition XL (9.50 [%]) ) are fully satisfied.

Further, FIG. 17 shows a characteristic diagram of saturation using a* and b* using the measurement angle θ of the protective film-equipped lens 1 according to Example 3 as a parameter. As is clear from FIGS. 15 and 17, the difference Sd between the saturations Sf and Ss is 0.34 when the measurement angle is 0 [°], 0.02 when the measurement angle is 10 [°], and 0.02 when the measurement angle is 20 [°]. It is 0.11 when the measurement angle is [°], and 0.13 when the measurement angle is 29 [°], both of which fully satisfy the saturation condition XS (2.70 or less).

In this way, Example 3 fully satisfies all the conditions required of the protective film-equipped lens 1 according to the present invention. Therefore, since sample E3 of Example 3 is in the smallest state among the examples, in the actual film forming process, it is also possible to provide it in multiple layers as shown in FIG. 2(b) described above.
[Reference example 1]

Next, the verification results according to Reference Example 1 are shown in FIGS. 18 to 21. FIG. 18 shows the film structure of the protective film-equipped lens 1 according to Reference Example 1.

Reference Example 1 shows the verification results when the brightness of each lens 1 with a protective film was varied. That is, sample G1 used glass material D having the highest refractive index (nd: 1.91) among the glass materials used for lens base 2, and used magnesium fluoride (nd: 1.37) as coating material C. Sample G2 used alumina (nd: 1.63) as coating material C, and sample G3 used lanthanum titanate (nd: 2.00) as coating material C. The measurement angle θ was set to 0 [°], the initial light intensity was set according to the type of coating material C, and the monitoring wavelength for control was 450 [nm] for sample G1 and 450 [nm] for sample G2. The wavelength was set at 480 [nm], and the wavelength for sample G3 was set at 500 [nm]. The number of layers is one.

FIG. 19 shows the data of the measurement results of the lens 1 with a protective film according to Reference Example 1, and FIG. , G3. As is clear from FIGS. 19 and 20, sample G1 has a physical film thickness of 92.34 [nm] and an optical film thickness (=(refractive index x physical film thickness)/wavelength) of 0.25. The maximum value of the rate difference Md is 10.00 [%], which does not satisfy the brightness condition XL (9.50 [%] or less). Sample G2 has a physical film thickness of 78.30 [nm] and an optical film thickness of 0.25, the maximum value of the reflectance difference Md is 7.47 [%], and the brightness condition XL (9.50 [%] or less). Sample G3 has a physical film thickness of 62.96 [nm] and an optical film thickness of 0.25, the maximum value of the reflectance difference Md is 3.39 [%], and the brightness condition XL (9.50 [%] or less). In addition,

Further, FIG. 21 shows a characteristic diagram of saturation using a* and b* of the protective film-equipped lens 1 according to Reference Example 1. As is clear from FIGS. 19 and 21, the difference Sd between the saturations Mf and Ms is 11.14 for sample G1, which does not satisfy the saturation condition XS (2.70 or less). Sample G2 has a saturation value of 3.75, which does not satisfy the saturation condition XS (2.70 or less). Sample G3 has a saturation value of 1.54, which satisfies the saturation condition XS (2.70 or less).

As shown in FIG. 18, the refractive indexes of the lens base 2 and the coating material C necessary for the lens 1 with a protective film satisfy the refractive index conditions. It can be confirmed that if the film thickness (physical film thickness [nm]) of the coating material C is made different by combination or film-forming treatment, the desired lens 1 with a protective film cannot be obtained.
[Reference example 2]

Next, the verification results according to Reference Example 2 are shown in FIGS. 22-25. FIG. 22 shows the film structure of the protective film-equipped lens 1 according to Reference Example 2.

In Reference Example 2, the glass material A (nd: 1.80) shown in FIG. 5 was used for the lens base 2, and lanthanum titanate (nd: 2.00) was used as the coating material C. Note that the measurement angle θ is 0 [°].

In particular, Reference Example 2 shows the verification results when the chroma of each protective film-equipped lens 1 was made different. Therefore, sample G4 has a physical film thickness of 62.96 [nm] and an optical film thickness of 0.25, and sample G5 has a physical film thickness of 125.92 [nm] and an optical film thickness of 0.50. , sample G6 has a physical film thickness of 188.88 [nm] and an optical film thickness of 0.75, and sample G7 has a physical film thickness of 251.84 [nm] and an optical film thickness of 1.00. Set. Further, FIG. 25 shows a characteristic diagram of saturation using a* and b* of the protective film-equipped lens 1 according to Reference Example 2.

In the case of Reference Example 2, the initial light amount is set according to the type of coating material C, and the monitoring wavelengths are 500 [nm] for sample G4, 550 [nm] for sample G5, 450 [nm] for sample G6, Sample G7 was set at 500 [nm]. The number of layers is one.

As is clear from FIGS. 23 to 25, sample G4 has a maximum value of the difference Md between the reflectances Mf and Ms of 6.64 [%], and satisfies the brightness condition XL (9.50 [%] or less). , and the difference Sd between the saturations Sf and Ss is 1.62, which satisfies the saturation condition XS (2.70 or less). On the other hand, in sample G5, the maximum value of the difference Md between the reflectances Mf and Ms is 7.18 [%] and satisfies the brightness condition XL (9.50 [%] or less), but the saturation Sf, The difference Sd between Ss is 6.17, which does not satisfy the saturation condition XS (2.70 or less). For sample G6, the maximum value of the difference Md between the reflectances Mf and Ms is 6.47 [%] and satisfies the brightness condition XL (9.50 [%] or less), but the difference Sd between the saturation Sf and Ss is 8. .48, which does not satisfy the saturation condition XS (2.70 or less). For sample G7, the maximum value of the difference Md between the reflectances Mf and Ms is 7.35 [%] and satisfies the brightness condition XL (9.50 [%] or less), but the difference Sd between the saturation Sf and Ss is 13 .05, which does not satisfy the saturation condition XS (2.70 or less).

In this way, the refractive indexes of the lens base 2 and the coating material C in the protective film-equipped lens 1 satisfy the refractive index conditions as shown in FIG. 22, but the combination of the glass material A and the coating material C, Alternatively, if the saturation condition XS is varied depending on the film thickness (physical film thickness [nm]) of the coating material C by the film forming process, it can be confirmed that the desired lens 1 with a protective film cannot be obtained.

Next, a method for forming a lens according to the present embodiment, that is, a method for manufacturing a lens 1 with a protective film, will be described according to the flowchart shown in FIG. 1 with reference to each figure.

First, the refractive index of the unformed lens base 2 to be used is selected from the range of 1.40 to 2.10 (step S1). For example, since the glass materials A, B, and C shown in FIG. 5 all satisfy this refractive index condition, they can be selected as the material for the lens base 2, although their characteristics may be superior or inferior.

Next, the reflectance Mf of the lens base 2, that is, the first reflectance Mf when the light R is vertically inputted, is measured using the measurement system shown in FIG. 3 (step S2). In this case, it is desirable to carry out the process over the entire optical wavelength range of 380-780 [nm] for the light R. Then, the measured first reflectance Mf is at least temporarily registered in a predetermined storage means (step S3).

In addition, the chroma Sf of the lens base 2, that is, the reflected light (measurement light Rm) when irradiated with the light R from the D65 standard light source, in the L*a*b* color space, One chroma saturation Sf is measured (step S4). Then, the measured first chroma Sf is at least temporarily registered in a predetermined storage means (step S5).

Next, the coating material C to be used is selected (step S6). In this case, the refractive index of the coating material C is selected from the range of 1.20-2.50. For example, the coating material C shown in FIG. 5 described above, specifically lanthanum titanate and alumina, all satisfy this refractive index condition, so any of them can be selected, although they may have better or worse properties.

Thereafter, the lens base 2 is set in a predetermined film forming apparatus (not shown) and a film forming process is performed (step S7). Note that for the film forming process, a known film forming method, specifically, a known method such as a wet film forming method, a vacuum evaporation method, a CVD method, an ALD method, etc., can be used. In this case, as described above, to control the film thickness during the film forming process, a flat plate made of a glass material having a refractive index nd of 1.523 (thickness: 1.35 [mm]) is also formed. Then, the film thickness is controlled by vertically making light R incident on this flat plate and measuring the magnitude of the second reflectance Ms (amount of light) of the reflected light Rm (monitoring wavelength). Thereafter, when the preset second reflectance Ms (light amount), that is, the termination condition is reached, the film forming process is terminated (steps S8 and S9). As a result, a lens 1m provided with the desired film-forming layer 3m can be obtained.

The lens 1m for which the film formation process has been completed is set in a predetermined measurement system shown in FIG. 3, and the second reflectance Ms is measured (step S10). Once the second reflectance Ms has been obtained, the difference Md from the temporarily registered first reflectance Mf is determined (step S11). Then, it is determined whether the difference Md satisfies the brightness condition XL (9.50 [%] or less) (step S12). At this time, if the conditions are not met, the product is treated as defective (step S13).

On the other hand, if the brightness condition XL is satisfied, second saturation Ss is measured (step S14). Once the second saturation Ss is obtained, the difference Sd from the temporarily registered first saturation Sf is determined (step S15). This difference Sd is calculated (operated) using the above-mentioned [Equation 1]. Then, it is determined whether the difference Sd satisfies the saturation condition XS (2.70 or less) (step S16). At this time, if the conditions are not met, the product is treated as defective (step S13). If the saturation condition XS is satisfied, it is determined to be a good product, and if an additional layer is provided, similar processing is performed (steps S17, S7, etc.). On the other hand, if layer formation by the film forming process is to be terminated, an inspection process such as a visual inspection is performed and the manufacturing is terminated (step S17). Thereby, the desired lens 1 with a protective film can be obtained.

As described above, according to the lens film forming method (protective film-equipped lens 1) according to the present embodiment, a lens base whose refractive index is selected from the range of 1.40 to 2.10 can be formed using the basic method and configuration. 2, and the refractive index of the coating material C is selected from the range of 1.20-2.50, and the first reflectance Mf of the lens base 2 itself and the coating layer of the coating material C on this lens base 2 are selected. By measuring the second reflectance Ms with a distance of 3 m, the difference Md between the first reflectance Mf and the second reflectance Ms is 9.50 [%] or less in the optical wavelength range of 380-780 [nm]. The first chroma Sf of the lens base 2 itself and the coating material on this lens base 2 in the L*a*b* color space when the brightness condition XL is satisfied and the light R from the D65 standard light source is irradiated. By measuring the second chroma Ss with 3 m of film-formed layer of C formed, the chroma saturation condition XS such that the difference Sd between the first chroma Sf and the second chroma Ss is 2.70 or less is satisfied. Since the protective film 3 is provided by applying the coating material C to the lens base 2, it is possible to easily perform the film formation process (film formation control) on the lens base 2. It is possible to provide a protective film 3 that is close to the above, and also to produce a highly homogeneous protective film 3. As a result, a lens 1 with a protective film that can not only ensure the necessary protection function for the target lens 1 with a protective film, that is, the lens base 2, but also generate good ghost flare that can be used for depiction effects, is obtained. be able to.

Although preferred embodiments including various examples and reference examples have been described in detail above, the present invention is not limited to such embodiments, and the present invention is not limited to detailed configurations, shapes, materials, quantities, numerical values, and methods. etc., any changes, additions, or deletions may be made without departing from the gist of the present invention.

For example, the lens base 2 has been shown as an example using various glass materials, but this does not preclude the use of various other glass materials or various plastic materials. Further, as the coating material C, various other coating materials including the coating materials exemplified in the examples can be applied. In particular, although the example coating material used is an optical film material, it is possible to apply various coating materials other than optical film materials that can produce the same effects as the present invention. Furthermore, although it is desirable to apply 380-780 [nm] to the predetermined optical wavelength range, this does not preclude application of optical wavelength ranges other than this optical wavelength range. On the other hand, the brightness condition XL is a condition in which the reflectance Mf, Ms for the incident light R perpendicular to the lens surface 2f is used, and the saturation condition XS is the reflection of the light R perpendicular to the lens surface 2f. The conditions for using the light as the measurement light Rm are not essential constituent requirements.

The method for forming a lens (lens with a protective film) according to the present invention can be used for various lenses used in cameras and the like.

1: lens with protective film, 2: lens base, 2f: lens surface, 3: protective film, 3m: film forming layer, (3ma): one layer, (3ma, 3mb...): two or more layers, C: coating material, R: incident light (incident light), Rm: measurement light, a*: a star, b*: b star

Claims (9)

A method for forming a lens film in which a protective film of a predetermined coating material is provided on a lens surface of a lens base, the lens base having a refractive index selected from a range of 1.40 to 2.10, and the coating material Select a refractive index from the range of 1.20 to 2.50, and measure the first reflectance of the lens base itself and the second reflectance of the lens base with a film formed layer of the coating material. By doing so, when the brightness condition is satisfied such that the difference between the first reflectance and the second reflectance is 9.50 [%] or less in a predetermined light wavelength range, and when irradiated with light from a D65 standard light source. By measuring the first chroma of the lens base itself and the second chroma of the lens base provided with the coating layer of the coating material in the L*a*b* color space, A method of forming a lens film, characterized in that a protective film is provided by performing a film forming process of the coating material so that the difference between the chroma and the second chroma saturation satisfies a chroma condition of 2.70 or less. 2. The lens film forming method according to claim 1, wherein the predetermined light wavelength range is a wavelength range of 380-780 [nm]. 2. The method of forming a film for a lens according to claim 1, wherein the brightness condition uses a reflectance for incident light perpendicular to the lens surface. 2. The lens film forming method according to claim 1, wherein the saturation condition uses reflected light of light incident perpendicularly to the lens surface as measurement light. 2. The saturation condition is characterized in that, when determining the difference between the first saturation and the second saturation, the difference between a* and b* in the L*a*b* color space is used. The method for forming the lens mentioned above. 2. The lens film forming method according to claim 1, wherein the film forming process of the coating material includes providing at least one film forming layer. 7. The lens forming layer according to claim 6, wherein when two or more of the film forming layers are provided, the film forming layer is added on the condition that the entire film satisfies the brightness condition and the saturation condition. Method. A lens with a protective film in which a protective film of a predetermined coating material is provided on the lens surface of a lens base, wherein the refractive index of the lens base is in the range of 1.40 to 2.10, and the refractive index of the coating material is is in the range of 1.20-2.50, and the difference between the first reflectance of the lens base itself and the second reflectance of the lens base with the coating layer formed on the coating material The first chroma of the lens base itself in the L*a*b* color space when the brightness condition is 9.50 [%] or less in the wavelength range and is irradiated with light from a D65 standard light source. A lens with a protective film, characterized in that the lens base is provided with a protective film that satisfies the saturation condition such that the difference in second saturation is 2.70 or less when the deposited layer of the coating material is provided on the lens base. 9. The lens with a protective film according to claim 8, wherein the coating material includes an optical film material.

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