JP5493824B2 - Optical component manufacturing method and optical component - Google Patents

Description

  The present invention relates to an optical component manufacturing method and an optical component.

  2. Description of the Related Art Conventionally, an optical component including a spherical lens is known as a kind of optical component used for collecting light in the optical communication field or the like. In such an optical component, an optical functional film such as a reflection suppressing film is formed on the surface of the spherical lens for the purpose of suppressing a decrease in light transmittance caused by light reflection on the surface of the spherical lens. It is generally done.

  However, since a spherical lens has a very large curvature compared with a normal lens, it is difficult to form an optical functional film on the surface of the spherical lens.

  In view of such a situation, various methods for forming an optical functional film on the surface of a spherical lens have been proposed in the following Patent Documents 1 to 3 and the like.

  Specifically, in Patent Document 1, by arranging a plurality of vapor deposition sources on an element support mechanism that can revolve or rotate, it is uniform for a lens with a large curvature supported by the element support mechanism. A method of forming an optical functional film having a thickness is described.

  In Patent Document 2, an optical functional film (filter film) having a uniform thickness is formed on the surface of a spherical lens by performing film formation while revolving while rotating the spherical lens around a rotation axis inclined in the vertical direction. ) Is described.

  In Patent Document 3, when a film-forming jig that revolves while rotating is positioned in the film-forming area, the state in which the film-forming material flies toward the central portion of the spherical lens is maintained. Describes a method of forming an optically functional film having a film thickness at the peripheral edge thinner than that at the center on the surface of the spherical lens.

JP-A-11-106901 JP 2006-342384 A JP 2007-108425 A

  However, as described in Patent Documents 1 and 2, when an optical functional film having a uniform thickness is formed on the surface of a spherical lens, it may be difficult to obtain desired optical characteristics. Similarly, as described in Patent Document 3, it may be difficult to obtain desired optical characteristics even when an optical functional film having a thinner peripheral film thickness than the central film thickness is formed on the surface of the spherical lens. is there.

  This invention is made | formed in view of this point, The objective is to provide the manufacturing method of the optical component which has a desired optical characteristic, and the optical component which has a desired optical characteristic.

  The manufacturing method of the optical component which concerns on this invention is related with the manufacturing method of an optical component provided with the spherical lens and the optical function film | membrane formed on the surface of a spherical lens. In the method for manufacturing an optical component according to the present invention, a spherical lens is provided around a second central axis that is tilted with respect to the first central axis, the central axis turning around the first central axis. While rotating, an optical functional film is formed by a vapor phase growth method.

  In the present invention, “turning” means a circular motion around an axis that does not pass through an object. On the other hand, “rotation” means a circular motion around an axis passing through an object.

  The optical characteristics of the optical functional film depend on the incident angle of light on the optical functional film. Specifically, the optical characteristics of the optical functional film shift by a shorter wavelength as the incident angle of light on the optical functional film increases. For example, when the optical functional film is a reflection suppressing film that suppresses reflection of light in a wavelength region equal to or shorter than a predetermined cutoff wavelength, the cutoff wavelength becomes shorter as the incident angle of light on the optical functional film increases. Wavelength shift.

  The optical characteristics of the optical functional film also depend on the film thickness of the optical functional film. More specifically, the optical characteristics of the optical functional film shift with a longer wavelength as the thickness of the optical functional film increases. For example, when the optical functional film is a reflection suppressing film that suppresses reflection of light in a wavelength region equal to or shorter than a predetermined cutoff wavelength, the cutoff wavelength is shifted by a longer wavelength as the thickness of the optical functional film increases. .

  In the present invention, the “film thickness of the optical functional film” means the film thickness in the normal direction of the surface of the spherical lens where the optical functional film is formed.

  Here, when collimated light or diffused light is incident on the optical functional film formed on the surface of the spherical lens, the incident angle of light at the portion located on the optical axis of the spherical lens is 0 °. On the other hand, as the distance from the optical axis of the spherical lens increases, the incident angle of light increases.

  Therefore, when the film thickness of the optical functional film is uniform, the optical characteristic of the optical functional film in the part away from the optical axis of the spherical lens is more than the optical characteristic in the part located on the optical axis of the spherical lens. Short wavelength shift. In other words, when a uniform optical functional film is designed so that desired optical characteristics are expressed with reference to the part located on the optical axis of the spherical lens, the optical characteristic in the part away from the optical axis of the spherical lens is The desired optical characteristics will be different. As a result, it becomes difficult to produce an optical component having desired optical characteristics as a whole.

  For example, when the optical functional film is a reflection suppression film that suppresses reflection of light in a wavelength range equal to or less than a predetermined cutoff wavelength, the cutoff wavelength of the reflection suppression film in a portion away from the optical axis of the spherical lens is used. There is a possibility that the reflectance of light in the portion away from the optical axis of the spherical lens becomes too high because it becomes shorter than the wavelength of light. In this case, it becomes difficult to produce an optical component having a desired light transmittance.

  As described in Patent Document 3, when an optical functional film having a thinner peripheral film thickness than the central film thickness is formed on the surface of the spherical lens, the incident angle of light is small and thick. The optical characteristics of the central portion, which is a film, and the peripheral portion, which has a large incident angle of light and is a thin film, are greatly different. As a result, it becomes more difficult to produce an optical component having desired optical characteristics.

  On the other hand, in the present invention, as described above, the central axis is turning around the first central axis and is around the second central axis that is inclined with respect to the first central axis. An optical functional film is formed by vapor phase growth while rotating the spherical lens. For this reason, the thickest part of the optical functional film is not the part located on the optical axis of the spherical lens, and the central part of the optical functional film is separated from the optical axis of the spherical lens. The film thickness increases. In such a case, variations in optical characteristics can be reduced compared to the case where the film thickness of the optical functional film is uniform in the central portion of the optical functional film. In particular, it is possible to reduce variations in optical characteristics in a portion away from the optical axis of the spherical lens. As a result, an optical component having desired optical characteristics can be obtained.

  For example, when the optical functional film is a reflection suppression film that suppresses reflection of light in the wavelength range below the predetermined cutoff wavelength, the situation where the cutoff wavelength in the part away from the optical axis of the spherical lens becomes too short is prevented. can do. Accordingly, it is possible to suppress an increase in light reflectance at a portion away from the optical axis of the spherical lens. As a result, an optical component having a desired high light transmittance can be obtained.

  The “spherical lens” refers to a lens in which at least one of the light entrance / exit surfaces is spherical, and the shape of the other part is not particularly limited to a spherical shape. The “spherical lens” includes, for example, a spherical lens body provided with a light entrance / exit surface and a flange portion or a recess provided in a portion other than the lens body.

In the present invention, the angle θ ₀ formed by the first central axis and the second central axis is greater than 0 ° and is ½ or less of the central angle θ ₁ of the region where the optical functional film is formed. It is preferable. If the angle θ ₀ is larger than ½ of the central angle θ ₁ , the film thickness of the portion located on the optical axis of the optical functional film becomes too thin, and the desired optical performance may not be obtained. .

  In the present invention, the type of vapor phase growth method is not particularly limited. For example, the optical functional film can be formed by a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method. In particular, the physical vapor deposition method is preferable because a two-dimensional optical functional film is more easily formed on the surface of the spherical lens than the chemical vapor deposition method. The physical vapor deposition method is sometimes called a sputtering method or a vacuum deposition method.

  The optical component according to the present invention can be suitably manufactured by the method for manufacturing an optical component according to the present invention. The optical component according to the present invention includes a spherical lens and an optical functional film. The optical functional film is formed on the surface of the spherical lens. In the optical component according to the present invention, the thickness of the central portion of the optical functional film when viewed from the direction in which the optical axis of the spherical lens extends increases as the distance from the optical axis of the spherical lens increases. Therefore, in the optical component according to the present invention, variations in optical characteristics are reduced in the central portion of the optical functional film as compared with the case where the film thickness of the optical functional film is uniform. As a result, the optical component according to the present invention can achieve higher optical characteristics. For example, when the optical functional film is a reflection suppressing film that suppresses reflection of light in a wavelength region equal to or less than a predetermined cutoff wavelength, the spherical functional lens has a uniform thickness compared to the case where the optical functional film has a uniform thickness. The cut-off wavelength in the part away from the optical axis is long. For this reason, the increase in the reflectance of the light in the part away from the optical axis of the spherical lens among optical components can be suppressed. Therefore, high light transmittance can be obtained.

  In addition, the film thickness of the outer peripheral part located outside the center part of the optical functional film when viewed from the direction in which the optical axis of the spherical lens extends is not necessarily increased as the distance from the optical axis of the spherical lens increases. . That is, in the entire optical functional film, the film thickness does not need to increase as the distance from the optical axis of the spherical lens increases. The film thickness of the outer peripheral portion may become thinner as the distance from the optical axis of the spherical lens increases.

  In the present invention, any part of the central portion of the optical functional film includes the intersection of the optical axis of the spherical lens and the optical functional film, and the spherical lens has a plane perpendicular to the optical axis of the spherical lens. It is preferable that it is located in the center side. The portion of the optical functional film that includes the intersection of the optical axis of the spherical lens and the optical functional film and is located on the opposite side of the center of the spherical lens from the plane perpendicular to the optical axis of the spherical lens. This is because if it exists in the center, the optical characteristics may deteriorate.

  In the present invention, the material of the spherical lens is not particularly limited. The spherical lens may be made of glass or resin, for example.

  The optical functional film is not particularly limited as long as it is a film having an optical function. The optical functional film is, for example, a reflection suppressing film that suppresses reflection of light in a predetermined wavelength range, a filter film having a wavelength selection function, an attenuation film that mainly attenuates light by absorption, or light in a predetermined wavelength range. A reflective film or the like that reflects may be used.

  The optical functional film can be constituted by, for example, a laminated film in which a low refractive index layer having a relatively low refractive index and a high refractive index layer having a relatively high refractive index are alternately laminated. The low refractive index layer can be formed of, for example, an alkaline earth metal fluoride such as silicon oxide, aluminum oxide, or calcium fluoride. On the other hand, the high refractive index layer can be formed of, for example, titanium oxide, niobium oxide, lanthanum oxide, tantalum oxide, tungsten oxide, or the like.

It is a schematic diagram of the manufacturing apparatus of the optical component in one Embodiment of this invention. It is a schematic plan view of a support member. It is the typical sectional view which expanded a part of support plate. It is typical sectional drawing of the optical component manufactured in one Embodiment of this invention. It is a graph showing the film thickness of the optical function film | membrane (The wavelength selection filter film | membrane of 1310 nm and 1490 nm, 48 layer film | membrane) in the Example of this invention. In the graph shown in FIG. 5, the horizontal axis represents the incident angle of light on the optical functional film. The vertical axis represents the film thickness of the optical functional film. It is a graph showing the film thickness of the optical function film | membrane (The wavelength selection filter film | membrane of 1310 nm and 1490 nm, 48 layer film) in the comparative example of this invention. In the graph shown in FIG. 6, the horizontal axis represents the incident angle of light on the optical functional film. The vertical axis represents the film thickness of the optical functional film. It is a graph showing the light transmittance of the center part of the optical functional film in the Example of this invention, and the light transmittance of the corresponding part of the optical functional film in the comparative example of this invention.

  Hereinafter, an example of a preferred embodiment of the present invention will be described.

  FIG. 1 is a schematic diagram of an optical component manufacturing apparatus according to this embodiment. A manufacturing apparatus 1 shown in FIG. 1 is an apparatus for manufacturing the optical component of the present embodiment shown in FIG. Specifically, the manufacturing apparatus 1 is a film forming apparatus that performs electron beam evaporation.

  As shown in FIG. 1, the manufacturing apparatus 1 includes an apparatus main body 10 that partitions and forms a film formation chamber 10a. A pressure reducing mechanism 14 such as a pressure reducing pump is connected to the film forming chamber 10a. The film forming chamber 10 a can be depressurized by the depressurization mechanism 14.

  The film forming chamber 10 a is provided with a target 13 as a supply source, an electron gun 12, and a support mechanism 20. The support mechanism 20 includes a support board 21. The support plate 21 is provided to be rotatable about the first central axis C1 with respect to the film forming chamber 10a. The lower surface 21a of the support board 21 is formed in a dome shape.

As shown in FIGS. 1 and 2, a plurality of flat support plates 22 are attached to the lower surface 21 a of the support board 21. Each support plate 22 is provided at a position different from the first central axis C <b> 1 of the support board 21. Each support plate 22 is rotatable about the second central axis C2. The second central axis C2 is inclined with respect to the first central axis C1. In the present embodiment, the angle θ ₀ formed by the first central axis C1 and the second central axis C2 is 1 / of the central angle θ ₁ of the region where the optical functional film 33 shown in FIG. 4 is formed. 2 or less.

  The support board 21 and the support plate 22 are connected to the drive mechanism 11. The drive mechanism 11 rotates the support plate 21 around the first central axis C1 and rotates each of the plurality of support plates 22 relative to the support plate 21 around the second central axis C2. For this reason, each support plate 22 is turned around the first central axis C1 by the drive mechanism 11, and rotates around the second central axis C2 inclined with respect to the first central axis C1.

  As shown in FIGS. 2 and 3, a plurality of optical component bodies 30 are attached to the support plate 22 in a matrix with the second central axis C <b> 2 as the center. However, the optical component main body 30 is not attached on the second central axis C2 of the support plate 22.

  As shown in FIG. 3, the optical component body 30 includes a folder 31 and a spherical lens 32. The folder 31 is not particularly limited as long as it can hold the spherical lens 32. The folder 31 can be constituted by a cylindrical member made of metal or resin, for example.

  The spherical lens 32 is a spherical lens made of, for example, glass or resin. The spherical lens 32 is fixed to the folder 31. The method for fixing the spherical lens 32 to the folder 31 is not particularly limited. For example, the spherical lens 32 can be fixed to the folder 31 with a glass frit.

  Next, the manufacturing method of the optical component 34 (refer FIG. 4) using the said manufacturing apparatus 1 is demonstrated.

  First, the plurality of optical component bodies 30 are attached to the support plate 22. Next, as shown in FIG. 2, the support plate 22 is attached to the support board 21. Next, the film forming chamber 10a (see FIG. 1) is brought into a reduced pressure atmosphere by the pressure reducing mechanism 14, and a gas necessary for film forming is supplied to the film forming chamber 10a from a gas supply mechanism (not shown) as necessary. .

  Next, while driving the support plate 21 and the support plate 22 with the drive mechanism 11, the electron gun 12 is driven to scatter particles from the target 13, thereby forming a film on the surface of the spherical lens 32. For this reason, the film formation on the surface of the spherical lens 32 is a second axis that is tilted with respect to the first central axis C1 and that is centered around the first central axis C1. This is performed by a vapor phase growth method such as a physical vapor phase growth method while turning the spherical lens 32 around the axis C2.

  Therefore, as shown in FIG. 4, in the optical functional film 33 formed in this way, the film thickness of the outer peripheral part 33b becomes thinner as it goes away from the optical axis A of the spherical lens 32, and the film of the central part 33a. The thickness increases as the distance from the optical axis A of the spherical lens 32 increases. Therefore, as described above, variations in optical characteristics can be reduced in the central portion 33a of the optical function film 33 as compared with the case where the film thickness of the optical function film 33 is uniform. As a result, the optical component 34 having desired optical characteristics can be obtained.

  Note that any part of the central portion 33a of the optical functional film 33 is more than the plane P perpendicular to the optical axis of the spherical lens 32 including the intersection of the optical axis A of the spherical lens 32 and the optical functional film 33. It is preferably located on the center side of the spherical lens 32. This is because if the portion located on the opposite side of the center of the spherical lens 32 from the plane P is present in the central portion 33a of the optical function film 33, the optical characteristics may be deteriorated.

  Moreover, it is preferable that the turning angular velocity of the support board 21 and the turning angular velocity around the second central axis C2 of the support plate 22 are different from each other.

(Example)
With the manufacturing method described above, the optical component shown in FIG. 4 was manufactured with the following design parameters. And the film thickness of the optical function film | membrane of an optical component was measured with the transmission scanning microscope. The result is shown in FIG. In the graph shown in FIG. 5, the horizontal axis represents the incident angle of light on the optical functional film. The vertical axis represents the film thickness of the optical functional film. A general single mode optical fiber (SMF) is used for the light exit port, and a spherical lens made of a glass material having a refractive index Nd of 1.8 and a spherical diameter of 2.0 mm is used.

  A light beam was incident on the center of the optical functional film, and the light transmittance of the optical component was measured using a tunable laser and a power meter. Similarly, the light transmittance was also measured for the optical component main body before the optical functional film was formed. From these results, the light transmittance of the central part of the optical functional film was obtained. The result is shown in FIG.

  Film structure of optical functional film: Film structure shown in Table 1 below

(Comparative example)
During film formation, the support plate 22 was not rotated about the second central axis C2, but only the support plate 21 was rotated about the first central axis C1. An optical component was produced, and the film thickness and light transmittance of the optical functional film were measured. The results are shown in FIGS. In the graph shown in FIG. 6, the horizontal axis represents the incident angle of light on the optical functional film. The vertical axis represents the film thickness of the optical functional film. A general SMF is used for the light exit port, and a spherical lens made of glass with Nd 1.8 and a spherical diameter of 2.0 mm is used.

  From the results shown in FIGS. 5 and 7, according to the present invention, the second central axis C2 that is pivoted about the first central axis C1 and that is inclined with respect to the first central axis C1. It can be seen that by forming the optical functional film while rotating the spherical lens around, an optical functional film can be formed in which the thickness of the central portion increases as the distance from the optical axis A of the spherical lens increases.

  Further, by increasing the thickness of the central portion of the optical functional film as the distance from the optical axis A of the spherical lens increases, high optical characteristics can be obtained. In other words, among the diffused light emitted from the optical fiber, the optical characteristics of the light incident obliquely on the film surface are shifted to a short wavelength. However, by increasing the film thickness, the short wavelength shift can be corrected and the optical axis can be corrected. The same optical characteristics can be obtained.

DESCRIPTION OF SYMBOLS 1 ... Manufacturing apparatus 10 ... Apparatus main body 10a ... Film-forming chamber 11 ... Drive mechanism 12 ... Electron gun 13 ... Target 14 ... Decompression mechanism 20 ... Support mechanism 21 ... Support board 21a ... Lower surface 22 of support board ... Support plate 30 ... Optical component Main body 31 ... Folder 32 ... Spherical lens 33 ... Optical functional film 33a ... Optical functional film central part 33b ... Optical functional film outer peripheral part 34 ... Optical component C1 ... First central axis C2 ... Second central axis

Claims (7)

In an optical component comprising a spherical lens and an optical functional film formed on the surface of the spherical lens,
An optical component in which the thickness of the central portion of the optical functional film when viewed from the direction in which the optical axis of the spherical lens extends increases as the distance from the optical axis of the spherical lens increases. Any part of the central portion of the optical functional film includes an intersection of the optical axis and the optical functional film, and is located closer to the center of the spherical lens than a plane perpendicular to the optical axis. The optical component according to claim 1 . The thickness of the outer peripheral portion located outside the central portion of the optically functional film when viewed from the direction of extension of the optical axis of the spherical lens, claim thinner as the distance from the optical axis of the spherical lens 1 Or the optical component of 2 . The optical component according to any one of claims 1 to 3 , wherein the optical functional film is a filter film having a wavelength selection function or a reflection suppressing film that suppresses reflection of light. The optical functional film is a laminated film in which a low refractive index layer having a relatively low refractive index and a high refractive index layer having a relatively high refractive index are alternately laminated. The optical component according to any one of the above. In the manufacturing method of the optical component as described in any one of Claims 1-5 ,
A support plate is provided so as to be rotatable about a second central axis that is pivoted about the first central axis and is inclined with respect to the first central axis. Place the target so that the target surface is not parallel to the plate,
The spherical lens is mounted on the support plate, and the spherical plate is rotated by the physical vapor deposition method while rotating the support plate around the first central axis while rotating the support plate around the first central axis. A method for manufacturing an optical component, wherein the optical functional film is formed on the surface of the optical component. Said first angle theta ₀ of the center shaft and the second central axis of, according to claim 6 wherein the optically functional film is 1/2 or less of the area formed of the center angle theta ₁ Manufacturing method of optical components.

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