JP2013000719A - Method for forming thin film and method for producing optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a thin film and a method for producing an optical element, which can easily reduce fluctuation in film thickness due to stagnation of a thin film-forming material on the outer edge of an object on which the film is to be formed.SOLUTION: The method for forming the thin film includes supplying the liquid thin film-forming material 9 to a convex part 10a on the object 10 on which the film is to be formed, and rotating the object 10 so as to apply and spread the thin film-forming material 9 on the convex part 10a and an edge flat surface 10b, thereby forming the film. In the method, before the object 10 is rotated, an application guide surface 10c for guiding the thin film-forming material 9 from the outer edge of the edge flat surface 10b further outward is provided.

Description

  The present invention relates to a thin film forming method and an optical element manufacturing method.

Conventionally, when forming a thin film, a dry process such as a vacuum evaporation method or a sputtering method is used. However, when a thin film is formed on a film-deposited body having a finite curvature such as a lens, the incident angle of the thin film-forming particles that form the thin film varies depending on the curvature of the film-forming surface in the dry process, so the film thickness is uniform. There is a problem that it is difficult to form a thin film. In addition, since a film cannot be formed in an air atmosphere in the dry process, a vacuum chamber or the like is required, and there is a problem that the apparatus becomes large.
For this reason, in place of the dry process, a wet process (wet process) that can easily achieve film thickness uniformity even on a film-forming surface having a finite curvature or a film-forming surface with a large area and that can be formed even in an air atmosphere. ) Has been proposed. The wet process is a method of forming a film by applying a liquid to a substrate and drying and heat-treating it by spin coating, dipping, spraying, roll coating, or the like.
For example, in the spin coating method, a liquid thin film forming material is dropped on a film formation body, and the film formation body is rotated at a high speed. The dropped thin film forming material spreads along the film formation body in a short time by centrifugal force, and a thin film having a uniform film thickness is formed. At this time, the film thickness is determined by the number of rotations of the film formation body, the type of thin film forming material, concentration, viscosity, dripping amount, temperature and humidity environment, and the like.
However, when the rotational speed of the film formation body or the outer diameter of the film formation body is too small, the centrifugal force may not reach a magnitude that exceeds the force for stopping the thin film forming material on the film formation surface. In this case, there is a problem in that the thin film forming material stays and rises at the outer edge portion, and the film thickness at the outer edge of the film formation body increases.
For this reason, in patent document 1, it has the thin film uniform part which has a spray nozzle for spraying an air current with respect to the swelling of the material film formed in the peripheral part area | region of a board | substrate, and this spray nozzle is a peripheral part area | region of a board | substrate. A film forming apparatus installed to blow an airflow of a predetermined flow rate on the material film obliquely with a predetermined angle with respect to the substrate and from the inside of the substrate toward the outside. Are listed. In addition, a film forming method for forming a film by this is described.

JP 2010-164871 A

However, the conventional thin film forming method as described above has the following problems.
In the technique described in Patent Document 1, since the film thickness of the material film changes depending on the flow rate of airflow and the direction of spraying, it is necessary to determine the conditions of the flow rate of airflow and the direction of spraying. If there is a premise that the material film is a resist film and the shape of the substrate is limited to a flat plate as described in Patent Document 1, it may be possible to reduce the time for setting the conditions.
However, for example, when the shape of the film formation surface is composed of various curved surfaces, such as an optical element, or when the allowable film thickness error of the thin film is small, it is highly accurate according to the individual conditions of the film formation target. It is necessary to perform conditions by conducting a simple experiment. For this reason, the work time required for setting the conditions becomes enormous, and the airflow generator is also required to have highly accurate control characteristics. Therefore, there is a problem that the cost for setting conditions and the cost of the airflow generation device increase.

  The present invention has been made in view of the above problems, and a thin film deposition method and an optical element that can easily reduce variations in film thickness due to retention of a thin film forming material at an outer edge portion of a deposition target. It aims at providing the manufacturing method of.

  In order to solve the above problems, the thin film deposition method of the present invention supplies a liquid thin film forming material to a deposition surface on a deposition target, and rotates the deposition target to rotate the deposition target. A thin film forming method for forming a film by spreading the thin film forming material on a film forming surface, wherein the thin film forming material is removed from an outer edge of the film forming surface before rotating the film forming object. A method of providing a coating guide surface for guiding outward is provided.

  In the thin film deposition method of the present invention, the deposition target is more outwardly formed by resin molding from the deposition target body including the deposition target surface and the outer periphery of the deposition target body. Preferably, the coating guide surface is provided at a position adjacent to the film formation surface on the projection.

  In the thin film deposition method of the present invention, it is preferable that the protrusion is cut off from the deposition target body after deposition.

  In the thin film deposition method of the present invention, it is preferable that the protrusion includes the resin-molded gate.

  In the thin film forming method of the present invention, the application guide surface is a flat surface or a curved surface, and when the target application thickness of the thin film forming material is h, the application guide surface and the film formation surface are formed. It is preferable that the height of the coating guide surface with respect to the film formation surface at the boundary is 0 or more and h or less.

  In the thin film forming method of the present invention, it is preferable that the thin film forming material reaching the outer edge of the film formation surface is scattered through the application guide surface by a centrifugal force during rotation of the film formation target. .

  The optical element manufacturing method of the present invention is a method of manufacturing an optical element by forming a thin film on the film-forming body using the thin film forming method of the present invention.

  According to the thin film forming method and the optical element manufacturing method of the present invention, the coating guide surface for guiding the thin film forming material further outward from the outer edge of the film forming surface is provided before the film forming body is rotated. Therefore, the retention of the thin film forming material at the outer edge portion of the film formation surface can be reduced, so that variations in film thickness due to the retention of the thin film forming material at the outer edge portion of the film formation surface can be easily reduced. There is an effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view and a plan view illustrating a configuration of a thin film deposition apparatus and a deposition target used in a thin film deposition method according to a first embodiment of the present invention. Manufactured by a schematic plan view and a front view of a film formation target used in the thin film deposition method according to the first embodiment of the present invention, and by the method of manufacturing an optical element according to the first embodiment of the present invention. It is a typical front view of an optical element. It is a typical graph which shows an example of the spectral reflectance characteristic of the thin film formed into a film by the thin film forming method which concerns on the 1st Embodiment of this invention. It is a typical top view explaining the process of the thin film forming method which concerns on the 1st Embodiment of this invention. It is AA sectional drawing and BB sectional drawing in FIG. It is typical sectional drawing explaining the process of the thin film forming method which concerns on the modification (1st modification, 2nd modification, 3rd modification) of the 1st Embodiment of this invention. It is typical sectional drawing explaining the effect | action in the projection part of a 1st and 2nd comparative example. Manufactured by a schematic plan view and a front view of a film formation target used in a thin film deposition method according to a fourth modification of the first embodiment of the present invention, and an optical element manufacturing method according to the fourth modification. It is the typical front view of an optical element. The typical top view of the to-be-film-formed body used for the thin film forming method which concerns on the 5th modification of the 1st Embodiment of this invention, its CC sectional drawing, and manufacture of the optical element which concerns on a 5th modification It is a typical front view of the optical element manufactured by the method. The typical top view of the to-be-deposited body used for the thin film forming method which concerns on the 6th modification of the 1st Embodiment of this invention, its DD sectional drawing, and manufacture of the optical element which concerns on a 6th modification It is a typical front view of the optical element manufactured by the method. Manufactured by a schematic plan view and front view of a film formation target used in a thin film deposition method according to a seventh modification of the first embodiment of the present invention, and by an optical element manufacturing method according to the seventh modification. It is the typical front view of an optical element. Manufactured by a schematic plan view and front view of a film formation target used in a thin film deposition method according to an eighth modification of the first embodiment of the present invention, and by an optical element manufacturing method according to the eighth modification. It is the typical front view of an optical element. It is the typical top view which shows the structure of the thin film film-forming apparatus and film-forming body used for the thin film film-forming method concerning the 2nd Embodiment of this invention, and its EE sectional drawing.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
A method for forming a thin film and a method for manufacturing an optical element according to the first embodiment of the present invention will be described.
FIGS. 1A and 1B are a schematic cross-sectional view and a plan view showing the configuration of a thin film deposition apparatus and a deposition target used in the thin film deposition method according to the first embodiment of the present invention. . FIGS. 2A and 2B are a schematic plan view and a front view of a film formation target used in the thin film formation method according to the first embodiment of the present invention. FIG.2 (c) is a typical front view of the optical element manufactured by the manufacturing method of the optical element which concerns on the 1st Embodiment of this invention. FIG. 3 is a schematic graph showing an example of spectral reflectance characteristics of a thin film formed by the thin film forming method according to the first embodiment of the present invention. The horizontal axis indicates the wavelength (nm), and the vertical axis indicates the reflectance (%).

  As shown in FIG. 1A, the thin film deposition apparatus 1 used in the thin film deposition method of the present embodiment supplies a liquid thin film forming material 9 onto the deposition target 10, and the deposition target 10 is It is an apparatus for forming a thin film by the liquid thin film forming material 9 by rotating.

As shown in FIGS. 2A and 2B, the film formation target 10 includes a film formation main body 10A and a protrusion 10B.
The deposition target body 10A includes a back surface portion 10d having a circular plane in plan view on one side, and a rotationally symmetric convex surface portion 10a on one side opposite to this and a cover made of a plane parallel to the back surface portion 10d. A flat surface 10b.
The shape of the convex surface portion 10a is not particularly limited as long as it is a curved surface having a convex rotational symmetry surface and good surface accuracy. For example, a rotationally symmetric surface such as a spherical surface, an axially symmetric aspherical surface, or a spheroidal surface can be employed.
The back surface portion 10d and the edge flat surface 10b are planes orthogonal to the optical axis O that is the central axis of the convex surface portion 10a.
A side surface portion 10e made of a cylindrical surface coaxial with the optical axis O is formed on the outer peripheral portion of the film formation body 10A.
With such a configuration, the deposition target body 10A includes a lens portion 10L having a lens action at the center portion by the convex surface portion 10a and the back surface portion 10d, and a circle extending radially outward from the side surface of the lens portion 10L. It has a shape of a convex flat lens with a flat edge comprising an annular flat edge portion 10F.

  The protrusion 10B is a rod-like protrusion that protrudes outward from one place on the side surface 10e along the radial direction passing through the optical axis O. In the present embodiment, the cross section is rectangular. The thickness of the protrusion 10B in the direction along the optical axis O is the same as the thickness of the edge flat portion 10F, and the front and back surfaces of the edge flat portion 10F are aligned with the edge flat surface 10b and the back surface portion 10d, respectively.

The length of the protrusion 10B is preferably set to such a length that the thin film forming material 9 is scattered radially outward by the centrifugal force acting on the thin film forming material 9 reaching the outermost periphery of the protrusion 10B.
The length of the protrusion 10B necessary for the thin film forming material 9 to be scattered radially outward is the density and viscosity of the thin film forming material 9, the material and surface properties of the protrusion 10B, and the film formation target 10 rotated. Depends on the rotation speed For this reason, these conditions are set appropriately, and an appropriate length is set in advance by simulating the balance of forces acting on the thin film forming material 9 at the end of the protrusion 10B or conducting an experiment. You just have to.

In the present embodiment, the optical thin film 12 (thin film) having a constant thickness is formed on each of the convex surface portion 10a, the edge flat surface 10b, and the back surface portion 10d of the film formation target 10 as the film formation surfaces. Then, the refractive index of the surface is adjusted, and the optical element 11 composed of a convex flat lens with a flat edge as shown in FIG.
The lens effective area of the optical element 11 may be limited to, for example, a circular area at the center of the convex surface portion 10a. However, in the present embodiment, the entire convex surface portion 10a is set as the lens effective region. explain.
The lens effective diameter of the optical element 11 (in this embodiment, the outer diameter of the convex surface portion 10a) can be appropriately selected as necessary. In this embodiment, for example, the lens effective diameter is 10 mm or less. This is particularly suitable for small-diameter lenses.

As an example of the dimension of the film formation target 10, the outer diameter of the side surface portion 10e is 6 mm, the outer diameter of the convex surface portion 10a is 5 mm, the thickness of the edge flat portion 10F is 1 mm, and the length of the protruding portion 10B is 4 mm. Can be mentioned.
Further, the film formation target 10 may be formed by cutting and polishing a glass material, for example, but in this embodiment, it is formed by resin molding.
The resin material of the film formation target 10 is not particularly limited as long as it can be used for optical lens applications. For example, acrylic, polycarbonate, or the like can be used. In this embodiment, a cycloolefin polymer having a refractive index n _d = 1.531 is used as an example. Here, “n _d ” is the refractive index at the d-line.

  In addition, when the film formation target 10 is formed by resin molding, the protruding portion 10B may be formed by transferring the shape of the cavity. However, in this embodiment, at least the shape cured by the gate portion for molding is used. It is formed by remaining in the molded product. That is, after taking out the molded product, the resin portion corresponding to the gate portion or the runner portion is cut into a predetermined length.

As the optical thin film 12, an appropriate film configuration can be adopted according to the optical characteristics required for the convex surface portion 10a and the back surface portion 10d. In this embodiment, as an example, in order to improve the transmittance, an example in which a silica sol having a refractive index of 1.26 at a wavelength of 520 nm is formed to a film thickness of 103 nm will be described.
As shown in FIG. 3, the spectral reflectance characteristics of the optical thin film 12 are as follows. The reflectance at a wavelength of 350 nm is about 2.3%, the reflectance decreases as the wavelength increases, and the reflectance at a wavelength of 520 nm is increased. The minimum value is about 0.04%, and the reflectance gradually increases as the wavelength increases, and the reflectance at the wavelength 750 becomes about 0.99%.
Therefore, the optical thin film 12 is an antireflection film that improves the transmittance in the visible region.

  As shown in FIGS. 1A and 1B, the schematic configuration of the thin film deposition apparatus 1 includes a holding jig 2, a suction unit 8, a support base unit 3, a drive motor 5, and a material dropping unit 7.

The holding jig 2 is a member that holds the film formation body 10 so as to be rotatable about the vertical axis, and is arranged along the vertical axis at the center of the disk portion 2b disposed horizontally and the lower surface side of the disk portion 2b. And a rotating shaft 2d extending in the direction.
In addition, the disc part 2b is provided so that attachment or detachment is possible, and in FIG. 1 (a), the convex part 10a, the edge flat surface 10b, and the application | coating guide surface 10c of the to-be-deposited body 10 face the vertically upward direction. The disk part 2b in the case of hold | maintaining is drawn.
Since the shape of the disk portion 2b when the optical thin film 12 is formed on the back surface portion 10d is easily understood by those skilled in the art, hereinafter, unless otherwise specified, the convex surface portion 10a and the edge flat surface 10b are optically coupled. A configuration example in the case of forming the thin film 12 will be described.

A holding hole 2c is provided in the center of the upper surface 2a of the disk portion 2b to hold the back surface portion 10d of the film formation target 10 from the lower surface side.
The holding hole 2c has a plan view shape in which a C-shaped arc portion into which the side surface portion 10e of the film formation target body 10 can be inserted is provided coaxially with the central axis P of the rotating shaft 2d, and the opening in the circumferential direction of the arc portion is formed. A rectangular portion into which the outer periphery of the protruding portion 10B of the film formation target body 10 can be inserted is formed in the portion.
The depth of the holding hole 2c from the upper surface 2a is set to a depth at which the upper surface of the edge flat portion 10F and the protrusion 10B of the deposition target 10 protrudes from the upper surface 2a.
Further, a suction hole 2e penetrating through the rotary shaft 2d is provided along the central axis P on the bottom surface of the holding hole 2c.

An inner ring of the bearing 4 that rotatably supports the rotary shaft 2d is fixed to an intermediate portion of the rotary shaft 2d. Further, the outer ring of the bearing 4 is fixedly supported by a box-shaped support base 3 that supports the holding jig 2 from below.
For this reason, the lower end portion of the rotating shaft 2 d extends through the support base 3 from above and extends to the inside of the support base 3.

A drive motor 5 that rotationally drives the holding jig 2 is disposed inside the support base 3.
The output shaft of the drive motor 5 and the lower end portion of the rotary shaft 2d are connected to each other below the support base portion 3 via a transmission mechanism 6 including, for example, a gear train. Thereby, the rotational driving force of the drive motor 5 is transmitted to the rotational shaft 2d, and the holding jig 2 is rotationally driven around the vertical axis.
The rotational speed of the drive motor 5 is set to an appropriate rotational speed in which the rotational speed of the rotating shaft 2d is in the range of, for example, 2000 rpm to 8000 rpm in consideration of the reduction ratio of the transmission mechanism 6.

Further, a suction part 8 including a suction pump (not shown) is provided inside the support base part 3.
The suction part 8 is connected to the lower end part of the suction hole part 2e through the rotary joint 8a. Thereby, the suction part 8 sucks the air in the suction hole part 2e downward, and the film forming body 10 placed on the holding hole part 2c can be adsorbed and fixed to the bottom surface of the holding hole part 2c. It can be done.

  As described above, the example in the case where the disk portion 2b holds the convex surface portion 10a, the edge flat surface 10b, and the coating guide surface 10c of the film formation body 10 vertically upward has been described. In the case of forming a film on the back surface portion 10d, instead of the holding hole portion 2c, a disk portion having a holding hole portion that holds the back surface portion 10d so as to be rotatable about the vertical axis in a state where the back surface portion 10d faces vertically upward can be attached. That's fine. In this case, the suction hole 2e is preferably provided at a position where the edge flat surface 10b is sucked so as not to contact the convex surface 10a.

  The material dropping unit 7 supplies the thin film forming material 9 to the center position of the film formation surface of the film formation object 10 held by the holding jig 2. In the arrangement of the present embodiment with the convex surface portion 10a facing upward, the material dripping portion 7 is disposed above the holding jig 2 with the dripping port 7a directed toward the center of the convex surface portion 10a. The thin film forming material 9 to be delivered can be dropped by a certain amount toward the convex surface portion 10a.

Next, the operation of the thin film deposition apparatus 1 will be described focusing on the thin film deposition method of the present embodiment.
4A, 4B, and 4C are schematic plan views for explaining the steps of the thin film forming method according to the first embodiment of the present invention. Fig.5 (a) is AA sectional drawing in Fig.4 (a). FIG.5 (b) is BB sectional drawing in FIG.4 (c).

In order to form a thin film of the thin film forming material 9 on the convex surface portion 10a and the edge flat surface 10b by the thin film deposition apparatus 1, first, resin molding is performed, and the coating guide surface 10c is provided on the projection portion 10B. The film formation target 10 is formed.
In the present embodiment, since the protrusion 10B is formed by utilizing the shape of the gate portion, unlike normal molding, after the molded product is taken out, cutting at the gate position is not performed, and a predetermined upstream side of the gate is performed. Cut the gate or runner at the length position.

Next, in a state where driving of the drive motor 5 is stopped, the film formation target 10 is placed in the holding hole 2c with the convex surface portion 10a facing upward. Then, suction by the suction unit 8 is started, the film formation target 10 is sucked, and the position of the film formation target 10 in the holding hole 2c is fixed.
Thereby, the film-forming body 10 is held in a state where the edge flat surface 10b and the application guide surface 10c protrude from the upper surface 2a.
In the present embodiment, since the installation atmosphere of the thin film deposition apparatus 1 may be an air atmosphere, the deposition target 10 may be set manually, for example, or may be set using a robot or the like.

Next, a certain amount of thin film forming material 9 necessary for forming a thin film is dropped from the material dropping unit 7. As shown in FIG. 1A, the dropped thin film forming material 9 is supplied as a droplet to the center of the convex surface portion 10a. In the example of the present embodiment, the amount of the thin film forming material 9 is 5 μL.
When the thin film forming material 9 is dropped, the drive motor 5 is driven to start the rotation of the holding jig 2. In this embodiment, as an example, the holding jig 2 is rotated so that the number of rotations is 3000 rpm.

Thereby, a centrifugal force acts on the thin film forming material 9 on the convex surface portion 10a, and the thin film forming material 9 moves from the center to the outer peripheral side as shown in FIG. For this reason, the thin film forming material 9 spreads in a circular shape in plan view on the convex surface portion 10a and the edge flat surface 10b to be thinned to form the coating film 9A.
Furthermore, if the rotation is continued, the coating film 9A is spread over a range that covers the entire convex surface portion 10a and the edge flat surface 10b, and as shown in FIG. 4B, the coating film tip 9a becomes the edge flat surface 10b. Reach the outer edge of the.
At this time, under the condition of the outer diameter of the edge flat surface 10b and the rotation speed of the holding jig 2 in the specific example of the present embodiment, the centrifugal force acting on the coating film 9A reaching the outer edge of the edge flat surface 10b is The force for stopping the coating film 9A on the edge flat surface 10b at the outer edge of the flat surface 10b, for example, the surface tension of the coating film 9A cannot be exceeded. For this reason, the coating film 9A is not scattered radially outward from the outer edge portion of the edge flat surface 10b.
As a result, as shown in FIG. 5A, the thin film forming material 9 temporarily stays in the vicinity of the coating film tip 9a on the outer edge portion of the edge flat surface 10b excluding the boundary with the coating guide surface 10c. A thick part 9b thicker than the required film thickness is formed.

However, in the present embodiment, a coating guide surface 10c composed of a horizontal plane continuous with the edge flat surface 10b is connected to a part of the outer edge portion of the edge flat surface 10b. For this reason, as shown in FIG.4 (c), the thin film forming material 9 moves on the application | coating guide surface 10c in the outer edge part of the edge flat surface 10b which touches the application | coating guide surface 10c. As a result, the thinning proceeds and the surplus film portion 9B is spread on the application guide surface 10c.
At this time, as a result of the film thickness decreasing at the boundary with the application guide surface 10c, the thin film forming material 9 of the thick wall portion 9b temporarily formed on the outer edge of the edge flat surface 10b becomes the boundary with the application guide surface 10c. It flows into the department. As a result, the thick part 9b disappears.

Next, when the surplus film portion 9B spread on the application guide surface 10c reaches the radial end of the application guide surface 10c, the force for stopping the surplus film portion 9B on the application guide surface 10c is applied to the application guide surface 10c. The centrifugal force increases in proportion to the square of the radius of rotation, whereas the force is not much different from the force that stops the thick portion 9b on the coating guide surface 10c at the outer edge portion of 10c. For this reason, by setting the radial dimension of the protrusion 10B as appropriate, a part of the surplus film portion 9B can be scattered outside the protrusion 10B as the scattering body 9C.
As a result, since the surplus film portion 9B does not stay on the application guide surface 10c, the surplus thin film forming material 9 gathered at the outer edge portion of the edge flat surface 10b continues without forming the thick portion 9b. Thus, it flows onto the application guide surface 10c. As a result, the thickness of the coating film 9A on the convex surface portion 10a and the edge flat surface 10b is made uniform.
In this way, after the film formation target 10 is rotated at 3000 rpm for 10 seconds by the drive motor 5, the drive motor 5 is stopped.
Thereby, a film thickness of 103 nm of the optical thin film 12 could be obtained.

Next, the suction by the suction unit 8 is stopped, the film-forming body 10 is removed from the holding jig 2, put into a drying furnace (not shown) that has been heated to 80 ° C. in advance, and heated for 10 minutes. The coating film 9A is cured.
This is the end of the thin film formation method of the present embodiment.

Next, the manufacturing method of the optical element of this embodiment is performed.
In this manufacturing method, as shown in FIG. 2B, the protrusion 10 </ b> B is cut out from the film formation target 10 on which the optical thin film 12 is formed by the cutter 13. Thereby, as shown in FIG.2 (c), the optical element 11 in which the optical thin film 12 was formed on the convex-surface part 10a and the edge flat surface 10b is manufactured.
Since the protruding portion 10B is a resin portion cured at the gate portion, the cutter 13 can use a tool for cutting the gate in normal resin molding.
In the present embodiment, the cutting surface 11a is formed in a shape that does not protrude from the outer diameter of the side surface portion 10e depending on the shape of the cutting edge of the cutter 13, but the cutting surface 11a protrudes outward in the radial direction from the side surface portion 10e. In the case where cutting burrs are generated, post-processing such as cutting or polishing the cut surface 11a may be performed following such a cutting step.

As described above, according to the thin film forming method and the optical element manufacturing method of the present embodiment, before the film formation target 10 is rotated, the thin film forming material 9 is removed from the outer edge portion of the coating guide surface 10c that is the film formation surface. The retention of the thin film forming material 9 at the outer edge portion of the film formation surface can be reduced by providing the application guide surface 10c that guides more outward. For this reason, the film thickness dispersion | variation by the retention of the thin film formation material 9 in the outer edge part of a film-forming surface can be reduced. That is, according to the present embodiment, for example, compared with the conventional technique in which the thickness of the thick portion 9a is reduced by, for example, performing complicated conditions and then blowing an air flow with a spray nozzle, the coating guide surface 10c is formed. Since it is only necessary to extend the centrifugal force to a position where the centrifugal force becomes sufficiently large, variations in film thickness can be easily reduced.
The present embodiment is an example in which the coating guide surface 10c is provided integrally with the film formation target body 10A when the film formation target 10 is formed.

  Further, in the present embodiment, since the protrusion 10B is constituted by the gate portion, the resin part to be cut is an unnecessary part that is cut off even by normal resin molding, and therefore the protrusion 10B is formed by the shape of the cavity. Compared to the above, the resin material can be reduced.

[First Modification]
Next, a thin film deposition method and an optical element manufacturing method according to a first modification of the present embodiment will be described.
FIG. 6A is a schematic cross-sectional view illustrating a process of a thin film deposition method according to a modification (first modification) of the first embodiment of the present invention. Fig.7 (a) is typical sectional drawing explaining the effect | action in the projection part of a 1st comparative example.

This modification is different from the first embodiment in that a film formation body 20 shown in FIG. 6A is used in place of the film formation body 10 of the first embodiment. Hereinafter, a description will be given centering on differences from the first embodiment.
The film formation body 20 includes a protrusion 20B instead of the protrusion 10B of the film formation body 10.
The protrusion 20B is obtained by replacing the application guide surface 10c of the protrusion 10B with an application guide surface 20c that is an inclined surface that is inclined toward the back surface 10d as it goes outward from the edge flat surface 10b.
The inclination angle of the application guide surface 20c is set to an angle at which the thin film forming material 9 can flow from the edge flat surface 10b to the application guide surface 20c according to the magnitude of the centrifugal force. The inclination angle of the application guide surface 20c is preferably 45 degrees or less.
The film formation body 20 is produced by resin molding in the same manner as the film formation body 10. The protrusion 20B uses a resin-molded gate.

  According to this modification, when the film formation target 20 is rotated, the coating film tip 9a of the coating film 9A spread on the edge flat surface 10b is caused by centrifugal force as shown in FIG. It reaches the boundary with the application guide surface 20c (see the two-dot chain line in the figure). Since the edge flat surface 10b and the coating guide surface 20c are continuous without a step, the coating film 9A is spread on the coating guide surface 20c by the centrifugal force acting on the coating film 9A. For this reason, similarly to the first embodiment, it is possible to easily reduce the film thickness variation due to the retention of the thin film forming material 9 in the outer edge portion of the film formation surface.

The operation of this modification will be described in comparison with the first comparative example shown in FIG.
In the first comparative example shown in FIG. 7A, a protrusion having an upper surface 51c formed at a position lower than the edge flat surface 10b on the back surface 10d side instead of the protrusion 20B of the film formation target 20. This is an example in the case of using a deposition target 51 having 51B.
In this case, a step is formed at the boundary between the edge flat surface 10b and the upper surface 51c, and a side surface portion 10e remains on the outer edge portion of the edge flat surface 10b to form a right angle corner. For this reason, the coating film tip 9a that has reached the outer edge portion of the edge flat surface 10b is the same as the outer edge portion of the edge flat surface 10b that is not provided with the protrusion 10B in the first embodiment, The upper surface 51c cannot guide the thin film forming material 9 further outward from the outer edge of the film formation surface. Therefore, the thick portion 9b is formed over the entire periphery of the outer edge portion of the film formation target 51, and the thickness of the coating film 9A cannot be made uniform.

On the other hand, in the present modification, the edge flat surface 10b and the application guide surface 20c are connected at an obtuse angle, so that even if the application film 9A reaches the boundary with the application guide surface 20c, the application film The tip 9a does not generate a large surface tension that acts at a right-angled corner. For this reason, the thin film forming material 9 flows smoothly to the application guide surface 20c, and the surplus film part 9B is formed.
At this time, since the application guide surface 20c is inclined in the direction in which the gravity acts, when the surplus film portion 9B is formed, a gravitational force acts on the surplus film portion 9B. For this reason, a smoother flow is formed compared to the first embodiment. As a result, the scattering body 9C can be more efficiently scattered from the end of the application guide surface 20c.

  Further, the optical element 11 is manufactured by cutting off the protruding portion 20B of the film formation target 20 after film formation in the same manner as in the first embodiment.

[Second Modification]
Next, a thin film deposition method and an optical element manufacturing method according to a second modification of the present embodiment will be described.
FIG. 6B is a schematic cross-sectional view illustrating a process of the thin film deposition method according to the modification (second modification) of the first embodiment of the present invention. FIG. 7B is a schematic cross-sectional view for explaining the operation of the protrusion of the second comparative example.

This modification is different from the first embodiment in that a film formation body 21 shown in FIG. 6B is used instead of the film formation body 10 of the first embodiment. Hereinafter, a description will be given centering on differences from the first embodiment.
The film formation body 21 includes a protrusion 21 </ b> B instead of the protrusion 10 </ b> B of the film formation body 10.
The protrusion 21B is obtained by replacing the application guide surface 10c of the protrusion 10B with an application guide surface 21c that is an inclined surface that is inclined to the opposite side to the back surface 10d side as it goes outward from the edge flat surface 10b.
The inclination angle of the application guide surface 21c is set to an angle at which the thin film forming material 9 can flow from the edge flat surface 10b to the application guide surface 21c according to the magnitude of the centrifugal force. The inclination angle of the application guide surface 21c is preferably 45 degrees or less.
Further, the film formation body 21 is produced by resin molding in the same manner as the film formation body 10. The protrusion 21B uses a resin-molded gate.

  According to this modification, when the film formation target 21 is rotated, as shown in FIG. 6B, the coating film tip 9a of the coating film 9A spread on the edge flat surface 10b is caused by centrifugal force. It reaches the boundary with the application guide surface 21c. Since the edge flat surface 10b and the coating guide surface 21c are continuous without a step, the coating film 9A is spread on the coating guide surface 21c by the centrifugal force acting on the coating film 9A. For this reason, similarly to the first embodiment, it is possible to easily reduce the film thickness variation due to the retention of the thin film forming material 9 in the outer edge portion of the film formation surface.

The operation of this modification will be described in comparison with the second comparative example shown in FIG.
The second comparative example shown in FIG. 7 (b), in place of the projections 21B of HiNarumakutai 21, against edge flat face 10b and than the target coating thickness h protrudes by a large height H ₀ top This is an example in the case of using a film formation target body 52 having a protrusion 52B in which 52c is formed.
In this case, a wall-shaped step 52e rising at a right angle from the edge flat surface 10b is formed at the boundary between the edge flat surface 10b and the upper surface 52c. For this reason, the coating film tip 9a that has reached the outer edge of the edge flat surface 10b is blocked by receiving a reaction force directed from the step 52e toward the opposite side of the centrifugal force, and thus a thick portion 9b is formed. As a result, the thick portion 9b is formed over the entire circumference of the outer edge portion of the deposition target body 52, and the thickness of the coating film 9A cannot be made uniform.

  On the other hand, in the present modification, the edge flat surface 10b and the application guide surface 21c are connected at an obtuse angle, so that even if the application film 9A reaches the boundary with the application guide surface 21c, the application film Since no reaction force that can resist the centrifugal force is generated at the tip 9a, the thin film forming material 9 smoothly flows on the application guide surface 21c, and an excess film portion 9B is formed.

  Further, if the protruding portion 21B of the film formation target 21 after film formation is cut out in the same manner as in the first embodiment, the optical element 11 is manufactured.

[Third Modification]
Next, a thin film deposition method and an optical element manufacturing method according to a third modification of the present embodiment will be described.
FIG. 6C is a schematic cross-sectional view illustrating the steps of the thin film forming method according to the modification (third modification) of the first embodiment of the present invention.

This modification is different in that a film formation body 22 shown in FIG. 6C is used in place of the film formation body 10 of the first embodiment. Hereinafter, a description will be given centering on differences from the first embodiment.
The film formation body 22 includes a protrusion 22B instead of the protrusion 10B of the film formation body 10.
Protrusion 22B is provided in place of the coating the guide surface 10c of the protrusion 10B, with respect to the edge a flat surface 10b, the position protruding by a small height H ₁ than the target coating thickness h coated guide surface 22c. Therefore, a wall-shaped step 22e that rises at a right angle from the flat edge surface 10b is formed at the boundary between the flat edge surface 10b and the application guide surface 22c.
The film formation body 22 is produced by resin molding in the same manner as the film formation body 10. The protrusion 22B uses a resin-molded gate.

According to this modification, when the film-forming body 22 is rotated, as shown in FIG. 6C, the coating film tip 9a of the coating film 9A spread on the edge flat surface 10b is caused by centrifugal force. It reaches the boundary with the application guide surface 22c. The edge flat surface 10b and the coating guide surface 22c are continuous via a step 22e. However, since the height of the step 22e is lower than the target coating thickness h, the thin film forming material 9 gets over the step 22e. The coating is spread on the application guide surface 22c.
The surplus film portion 9B on the application guide surface 22c is temporarily thick as shown by a solid line in FIG. 6C, but as the rotation proceeds, the excess film portion 9B scatters from the end of the protrusion 22B as the scattering body 9C. To be reduced. For this reason, as indicated by a two-dot chain line in FIG. 6C, when the coating film 9A reaches the target coating thickness h, the coating film 9A is aligned on the same plane. Therefore, the surplus film portion 9B does not flow backward to the coating film 9A side after the rotation stops.
For this reason, similarly to the first embodiment, it is possible to easily reduce the film thickness variation due to the retention of the thin film forming material 9 in the outer edge portion of the film formation surface.

  Further, if the protrusion 22B of the film-formed body 22 after film formation is cut out in the same manner as in the first embodiment, the optical element 11 is manufactured.

[Fourth Modification]
Next, a thin film deposition method and an optical element manufacturing method according to a fourth modification of the present embodiment will be described.
8A and 8B are a schematic plan view and a front view of a film formation target used in the thin film formation method according to the fourth modification of the first embodiment of the present invention. FIG.8 (c) is a typical front view of the optical element manufactured by the manufacturing method of the optical element which concerns on the 4th modification of the 1st Embodiment of this invention.

This modification is different in that a film formation body 23 shown in FIGS. 8A and 8B is used instead of the film formation body 10 of the first embodiment. Hereinafter, a description will be given centering on differences from the first embodiment.
The film formation body 23 includes a film formation body main body 23 </ b> A instead of the film formation body 10 </ b> A of the film formation body 10.
The deposition target body 23A is a flat plate member provided with a flat surface portion 23a parallel to the back surface portion 10d, instead of the convex surface portion 10a and the edge flat surface 10b of the deposition target body main body 10A.
An effective application region 23b in which the film thickness of the optical thin film 12 falls within a substantially constant range is set in the flat surface portion 23a in the same range as the convex surface portion 10a of the film formation target 10.
In addition, the film formation body 23 is produced by resin molding in the same manner as the film formation body 10. The protrusion 10B uses a resin-molded gate.

  Since this modification is an example in which the convex surface portion 10a of the film formation target body 10 of the first embodiment is formed on a flat surface, the film formation target is the same as in the first embodiment. Variations in film thickness due to retention of the thin film forming material 9 at the outer edge of the surface can be easily reduced.

Further, as shown in FIG. 8C, if the protrusion 10B of the film formation target 23 after film formation is removed in the same manner as in the first embodiment, a substantially constant film is formed in the effective application region 23b. By forming the optical thin film 12 having a thickness, the optical element 33 having the optical characteristics shown in FIG. 3 is manufactured.
The optical element 33 is an example of a flat optical element having no refractive power.

[Fifth Modification]
Next, a thin film deposition method and an optical element manufacturing method according to a fifth modification of the present embodiment will be described.
FIG. 9A is a schematic plan view of a film formation target used in the thin film formation method according to the fifth modification of the first embodiment of the present invention. FIG. 9B is a cross-sectional view taken along the line CC in FIG. FIG.9 (c) is a typical front view of the optical element manufactured by the manufacturing method of the optical element which concerns on the 5th modification of the 1st Embodiment of this invention.

The present modification is different from the first embodiment in that a film formation body 24 shown in FIGS. 9A and 9B is used instead of the film formation body 10 of the first embodiment. Hereinafter, a description will be given centering on differences from the first embodiment.
The film formation body 24 includes a film formation body main body 24A and a protrusion 24B instead of the film formation body 10A and the protrusion 10B of the film formation body 10.

The deposition target body 24A includes a rotationally symmetric convex surface 24a having the optical axis O as a central axis, instead of the convex surface portion 10a and the edge flat surface 10b of the deposition target body 10A. In the example illustrated in FIG. 9B, a spherical surface is adopted as an example of the shape of the convex surface portion 24a.
On the convex surface portion 24a, a lens effective region 24b is set in the same range as the convex surface portion 10a in the film formation target body 10 so that the film thickness of the optical thin film 12 falls within a substantially constant range.

The protrusion 24B is a plate-like protrusion that protrudes outward from one place on the side surface 10e along the radial direction passing through the optical axis O. The application guide surface 24c is replaced with the application guide surface 10c of the protrusion 10B. Prepare.
The application guide surface 24c is a surface connected to the convex surface portion 24a in the protrusion 24B, and is formed as a rotationally symmetric surface extending in the radial direction with the same design shape as the convex surface portion 24a. In the example shown in FIG. 9B, it has a spherical shape with the same curvature as the convex surface portion 24a.
For this reason, the application | coating guide surface 24c is smoothly connected without the level | step difference with the outer edge part of the convex surface part 24a.
The film formation body 24 is produced by resin molding in the same manner as the film formation body 10.

In this modification, the convex surface portion 24a and the coating guide surface 24c are smoothly connected to each other like the edge flat surface 10b and the coating guide surface 10c of the film formation target 10 of the first embodiment. 24a and the application | coating guide surface 24c differ in the point which is the spherical surface which is a curved surface.
Further, the edge flat surface 10b and the coating guide surface 10c are flat surfaces extending in the direction along the centrifugal force, whereas the convex surface portion 24a and the coating guide surface 24c are obliquely downward (back surface portion 10d side) with respect to the centrifugal force. The point that extends is different.

According to this modification, although illustration is omitted, when the film formation target 24 is rotated, the coating film 9A is spread on the convex surface portion 24a as in the first embodiment, and the coating film 9A is applied. The film tip 9a reaches the boundary with the application guide surface 24c by centrifugal force. Since the convex surface portion 24a and the application guide surface 24c are smoothly continuous without any step, the application film 9A is spread on the application guide surface 24c by the centrifugal force acting on the application film 9A.
For this reason, similarly to the first embodiment, it is possible to easily reduce the film thickness variation due to the retention of the thin film forming material 9 at the outer edge portion of the convex surface portion 24a that is the film formation surface.
At this time, in the present modification, the coating guide surface 24c is inclined in the radial direction in the same manner as in the first modification, so that it is more efficient than the first embodiment. Therefore, the scattering body 9C can be scattered.

  Further, if the protrusion 24B of the film formation target 24 after film formation is cut out in the same manner as in the first embodiment, as shown in FIG. 9C, an optical element which is a convex flat lens without edge flatness. 34 is manufactured.

[Sixth Modification]
Next, a thin film deposition method and an optical element manufacturing method according to a sixth modification of the present embodiment will be described.
FIG. 10A is a schematic plan view of a film formation target used in the thin film deposition method according to the sixth modification of the first embodiment of the present invention. FIG.10 (b) is DD sectional drawing in Fig.10 (a). FIG.10 (c) is a typical front view of the optical element manufactured by the manufacturing method of the optical element which concerns on the 6th modification of the 1st Embodiment of this invention.

This modification is different in that a film formation body 25 shown in FIGS. 10A and 10B is used in place of the film formation body 24 of the fifth modification. Hereinafter, a description will be given centering on differences from the fifth modification.
The film formation target 25 includes a protrusion 25B instead of the protrusion 24B of the film formation target 24 of the fifth modified example.
The protrusion 25B is a plate-like protrusion that protrudes outward along the radial direction passing through the optical axis O from one place on the side surface 10e, and the application guide surface 25c is replaced with the application guide surface 24c of the protrusion 24B. Prepare.
The application guide surface 25c is a surface that is connected to the convex surface portion 24a in the protrusion 25B. As shown in FIG. 10B, the cross-sectional shape including the optical axis O is smoothly connected to the outer edge portion of the convex surface portion 24a. It is formed as a curved surface that draws a convex arcuate curve on the back surface portion 10d side. For this reason, the shape of the convex part 24a and the application | coating guide surface 25c in the cross section containing the optical axis O consists of a smooth curve which consists of a combination of a convex curve and a concave curve as a whole.
In the present modification, the cross-sectional shape along the circumferential direction of the application guide surface 25c is a rotationally symmetric surface with the optical axis O as the rotationally symmetric axis so that the molding die can be easily manufactured. In this case, the cross-sectional shape along the circumferential direction of the application guide surface 25c has a convex shape.
Further, the film formation body 25 is produced by resin molding in the same manner as the film formation body 10.

In the present modification, the convex surface portion 24a and the application guide surface 25c are smoothly connected as in the fifth modification, but the radial cross section of the application guide surface 25c is a concave curved surface. Different.
For this reason, when the film formation target 25 is rotated, although not shown in particular, when the surplus film portion 9B formed on the application guide surface 25c advances radially outward along the curved shape of the application guide surface 25c, the back surface portion After approaching 10d, it is spread along a concave shape that is separated from the back surface portion 10d. The surplus film portion 9B is scattered outside the film formation target 25 at the end of the application guide surface 25c.
At that time, since the bending direction of the application guide surface 25c changes from the lower side toward the upper side, the scattering body 9C can be scattered in a direction closer to the direction of the centrifugal force than in the fifth modified example. For this reason, even when the radius of curvature of the convex surface portion 24a is small, the scattering body 9C can be efficiently scattered.

[Seventh Modification]
Next, a thin film deposition method and an optical element manufacturing method according to a seventh modification of the present embodiment will be described.
FIGS. 11A and 11B are a schematic plan view and a front view of a film formation target used in the thin film deposition method according to the seventh modification of the first embodiment of the present invention. FIG.11 (c) is a typical front view of the optical element manufactured by the manufacturing method of the optical element which concerns on the 7th modification of the 1st Embodiment of this invention.

This modification is different in that a film formation body 26 shown in FIGS. 11A and 11B is used instead of the film formation body 10 of the first embodiment. Hereinafter, a description will be given centering on differences from the first embodiment.
The film formation body 26 is obtained by adding a plurality of protrusions 26 </ b> B to the film formation body 10. The number of the protrusions 26B is not particularly limited. Hereinafter, an example in which three protrusions 26B are provided will be described.
Each protrusion 26B is a rod-shaped protrusion having a rectangular cross section protruding outward from the side surface part 10e along the radial direction passing through the optical axis O, like the protrusion part 10B.
Such a protrusion 26B is formed integrally with the film formation body 10A by providing a corresponding concave shape in a mold for resin-molding the film formation body 26.
Thus, unlike the protrusion 10B, the protrusion 26B does not have the function of a resin-molded gate, and therefore, there is no restriction on the shape or position required for the gate. Therefore, the shape of each protrusion 26B may be exactly the same as the shape of the protrusion 10B or may be different. In this modification, as an example, it is formed in a rod shape whose width in the circumferential direction is narrower than that of the protrusion 10B, and is formed at a position where the circumference is equally divided into four with the protrusion 10B.

According to this modification, when the film formation body 26 is rotated, the coating film 9A is spread on the convex surface portion 10a and the edge flat surface 10b in the same manner as in the first embodiment. The coating film tip 9a of the film 9A reaches the boundary between the coating guide surfaces 10c and 26c by centrifugal force. On each application guide surface 26c, an excess film portion 9B is formed in the same manner as the application guide surface 10c, and the scattering body 9C is scattered from the end of the application guide surface 26c.
For this reason, similarly to the first embodiment, the film thickness variation due to the retention of the thin film forming material 9 at the outer edge portions of the convex surface portion 10a and the edge flat surface 10b which are the film formation surfaces can be easily reduced. .
At this time, in the present modification, since the coating guide surfaces 10c and 24c are provided radially at four locations on the outer edge portion of the edge flat surface 10b, the thin film can be formed more quickly than in the first embodiment. The material 9 is moved out of the edge flat surface 10b. As a result, for example, even if the material of the thin film forming material 9 is a material that tends to change in viscosity after application, the film thickness of the application film 9A can be made uniform easily.

  Further, if the protrusions 10B and 26B of the film formation target 26 after film formation are cut out in the same manner as in the first embodiment, as shown in FIG. 11C, a convex flat lens without edge flatness is obtained. The optical element 36 is manufactured. The optical element 36 has the same shape as the optical element 11 except that four cut surfaces 11a are formed on the side surface portion 10e.

[Eighth Modification]
Next, a thin film deposition method and an optical element manufacturing method according to an eighth modification of the present embodiment will be described.
FIGS. 12A and 12B are a schematic plan view and a front view of a film formation target used in the thin film deposition method according to the eighth modification of the first embodiment of the present invention. FIG. 12C is a schematic front view of the optical element manufactured by the optical element manufacturing method according to the eighth modification of the first embodiment of the present invention.

This modification is different in that a film formation body 27 shown in FIGS. 12A and 12B is used instead of the film formation body 10 of the first embodiment. Hereinafter, a description will be given centering on differences from the first embodiment.
The film formation body 27 includes a film formation body main body 27A and a protrusion 27B, respectively, instead of the film formation body 10A and the protrusion 10B of the film formation body 10 of the first embodiment.
The film formation body 27 </ b> A is configured by the lens portion 10 </ b> L of the film formation body 10.
The protruding portion 27B is obtained by expanding the outer diameter of the edge flat portion 10F of the deposition target body 10A to the position of the end portion of the protruding portion 10B, and replaces the outer flat surface 10b and the side surface portion 10e with outer diameters. Only a different edge flat surface 27b (application guide surface) and side surface portion 27e are provided.
Such a film-formed body 27 can be manufactured by resin molding using a mold.

According to this modified example, when the film formation target 27 is rotated, the coating film 9A is spread on the convex surface portion 10a as in the first embodiment, although not particularly illustrated. When the coating film 9A reaches the boundary with the edge flat surface 27b connected to the convex surface portion 10a, the coating film 9A is spread concentrically on the edge flat surface 27b in the same manner as in the first embodiment.
When the coating film 9A reaches the outer edge portion of the edge flat surface 27b, a force for stopping the coating film 9A on the edge flat surface 27b acts from the edge flat surface 27b. Since the same size as the position of the end portion of the application guide surface 10c of the first embodiment is provided, the centrifugal force becomes larger. As a result, the thin film forming material 9 is sequentially scattered outward from the outer edge portion of the edge flat surface 27b by centrifugal force.
For this reason, similarly to the first embodiment, the film thickness variation due to the retention of the thin film forming material 9 at the outer edge portions of the convex surface portion 10a and the edge flat surface 10b which are the film formation surfaces can be easily reduced. .

  In the present embodiment, a protrusion 27B that protrudes further outward from the outer peripheral portion of the film formation body 27A is provided on the entire outer periphery of the film formation body 27A, thereby forming an annular shape. It is an example.

  Further, if the projection 27B of the film formation target 27 after film formation is cut out in the same manner as in the first embodiment, as shown in FIG. 12C, an optical element that is a convex flat lens without edge flatness. 38 is manufactured. The optical element 38 is a member in which the optical thin film 12 is formed on the lens portion 10L of the film formation target 27, and a side surface is formed by a cylindrical cut surface 11a formed by cutting out the protrusion 27B. .

[Second Embodiment]
Next, a thin film deposition method and an optical element manufacturing method according to the second embodiment of the present invention will be described.
FIG. 13A is a schematic plan view showing the configuration of a thin film deposition apparatus and a deposition target used in the thin film deposition method according to the second embodiment of the present invention. FIG.13 (b) is EE sectional drawing in Fig.13 (a).

As shown in FIGS. 13A and 13B, the thin film deposition apparatus 40 used in the thin film deposition method of the present embodiment supplies a liquid thin film forming material 9 onto the deposition target 28, and the deposition is performed. In this apparatus, the film body 28 is rotated to form a thin film using the liquid thin film forming material 9.
The schematic configuration of the thin film deposition apparatus 40 includes a holding jig 41 in place of the holding jig 2 of the thin film deposition apparatus 1 in the first embodiment.
The film formation target 28 is obtained by removing the protrusion 10B from the film formation target 10 used in the first embodiment, and is composed only of the film formation target body 10A of the first embodiment.
Hereinafter, a description will be given centering on differences from the first embodiment.

  The holding jig 41 includes a disk part 42 in which only the holding hole part 2c is deleted from the disk part 2b, instead of the disk part 2b of the holding jig 2 of the first embodiment. A fixed holding portion 44 and a movement holding portion 43 are provided on the upper surface 2a of the first embodiment.

The fixed holding portion 44 is locked from the side to the side surface portion 10e of the film formation target 28 placed with the back surface portion 10d facing the upper surface 2a, and the optical axis O is aligned with the central axis P. A member for holding the film formation target 28.
In the present embodiment, the thickness is equal to or greater than the thickness of the edge flat portion 10F, and the protrusion height from the edge flat surface 10b of the film formation target 28 placed on the upper surface 2a is less than the target application thickness h. It consists of a substantially rectangular parallelepiped block-like member.
The fixed holding portions 44 are provided at two locations along two radial directions passing through the central axis P and intersecting each other at 120 °. At the end of each fixed holding portion 44 on the central axis P side, there is provided a locking surface 44a made of a cylindrical surface whose distance from the central axis P matches the radius of the side surface portion 10e and can be in close contact with the side surface portion 10e. It has been.

The application guide surface 44c, which is an upper surface adjacent to the upper end side of the locking surface 44a, is formed of a substantially rectangular flat surface extending in a strip shape outward along the radial direction passing through the central axis P parallel to the upper surface 2a. .
The length of the coating guide surface 44c along the radial direction is such that the thin film forming material 9 moves radially outward due to the centrifugal force acting on the thin film forming material 9 reaching the end opposite to the central axis P of the coating guide surface 44c. It is preferable to set the length to the extent of scattering. The length of the application guide surface 44c required for the thin film forming material 9 to be scattered radially outward is the density and viscosity of the thin film forming material 9, the material and surface properties of the application guide surface 44c, and the film formation target 28. Since it depends on the rotational speed of rotating, the balance of the force acting on the thin film forming material 9 at the end of the application guide surface 44c can be set to an appropriate value by simulating or conducting an experiment in advance. it can.

The movement holding unit 43 is provided so as to be movable back and forth with respect to the side surface portion 10e of the film formation target 28 placed with the back surface portion 10d facing the upper surface 2a, and when moving forward toward the central axis P, This is a member that holds the film formation body 28 at a position where the film formation body 28 is locked from the side and the optical axis O is aligned with the central axis P.
In the present embodiment, the movement holding portion 43 fixes the positions of the slide holding portion 43A and the slide holding portion 43A, which are held by the guide rail portion 43b provided on the upper surface 2a so as to be able to advance and retreat toward the central axis P. It is comprised by the clamp part 43B.
The outer shape of the slide holding portion 43A is an elongated, substantially rectangular parallelepiped shape similar to that of the fixed holding portion 44, and each fixed holding portion 44 is disposed at a position that divides the circumference around the central axis P into three equal parts. .
At the end of the slide holding portion 43A on the central axis P side, a locking surface 43a made of a cylindrical surface that can be in close contact with the side surface portion 10e is provided.
The application guide surface 45c, which is an upper surface adjacent to the upper end side of the locking surface 43a, is formed of a substantially rectangular plane extending outward in a strip shape along the radial direction passing through the central axis P parallel to the upper surface 2a. .
The height from the upper surface 2a of the coating guide surface 45c and the length along the radial direction are set similarly to the coating guide surface 44c.
As the configuration of the clamp portion 43B, for example, a configuration in which the side surface of the slide holding portion 43A is pressed and fixed by a fixing screw that advances and retreats with respect to the circumferential side surface of the slide holding portion 43A can be employed.

In order to form a thin film of the thin film forming material 9 on the convex surface portion 10a and the edge flat surface 10b of the film formation target 28 by the thin film formation apparatus 40, first, resin molding is performed, and the film formation target 28 is formed. Mold.
Next, in a state where the drive of the drive motor 5 is stopped, the clamp portion 43B is loosened and the slide holding portion 43A is retracted to a position away from the central axis P. And the to-be-film-formed body 28 is mounted in the center part of the upper surface 2a with the convex surface part 10a facing upward.
Next, the slide holding portion 43A is moved toward the central axis P to press the side surface portion 10e, and the locking surface 44a of each fixed holding portion 44 and the locking surface 43a of the slide holding portion 43A are moved to the side surface portion. Adhere to 10e.
Next, the position of the slide holding unit 43A is fixed by the clamp unit 43B, and suction by the suction unit 8 is started to suck the film formation target 28 and position the film formation target 28 on the upper surface 2a. Fix it.
In this way, as shown in FIGS. 13A and 13B, the coating guide surfaces 44 c, 44 c and 43 c are provided at three positions in the circumferential direction on the edge flat surface 10 b of the film formation target 28. Adjacent to each other.
At this time, the height from the upper surface 2a of the coating guide surfaces 44c, 44c, 43c is aligned with the same plane as the edge flat surface 10b, or a minute step in a range of a height lower than the target coating thickness h. Is formed.

  Such coating guide surfaces 44c, 44c and 43c are the same as the coating guide surface 10c of the first embodiment or the coating guide surface 22c of the third modification of the first embodiment. Is formed from the outer edge portion of the film forming surface to the outside.

Next, although not particularly shown, a certain amount of the thin film forming material 9 necessary for forming a thin film is dropped from the material dropping portion 7 in the same manner as in the first embodiment, and the drive motor 5 is driven to hold the film. The tool 2 starts to rotate.
As a result, as in the first embodiment, centrifugal force acts on the thin film forming material 9 on the convex surface portion 10a, so that the thin film forming material 9 is circular in plan view on the convex surface portion 10a and the edge flat surface 10b. The coating film 9 </ b> A is formed as the thickness of the coating film is reduced.
Furthermore, if the rotation is continued, the coating film 9A reaches the outer edge portion of the edge flat surface 10b, and temporarily forms the thick portion 9b similar to the first embodiment, but the thin film forming material 9 It moves radially outward on the coating guide surfaces 44c, 44c, 43c, is scattered outward from the outer peripheral end of the coating guide surfaces 44c, 44c, 43c, and is coated on the convex surface portion 10a and the edge flat surface 10b. The film thickness of the film 9A is made uniform.
In this way, the drive motor 5 is stopped after the rotation of the drive motor 5 is continued until the coating film 9A reaches the target coating thickness h before drying required for forming the optical thin film 12.

Next, the suction by the suction part 8 is stopped, and the clamp part 43B is unfixed to retract the slide holding part 43A radially outward. And the to-be-film-formed body 10 is removed from the holding jig 41, and it puts into the drying furnace of illustration not shown previously heated at 80 degreeC, and heats for 10 minutes, The coating film 9A is hardened.
Thereby, the optical thin film 12 having a film thickness of 103 nm ± 3 nm is formed on the convex surface portion 10a and the edge flat surface 10b.
This is the end of the thin film formation method of the present embodiment.
The surplus film portion 9B applied to the application guide surfaces 44c, 44c, and 43c is cleaned before another film formation target is formed.

  In the present embodiment, since there is no shape portion that is not necessary for the optical element such as the protrusion 10B, the first thin film forming method of the present embodiment is completed and the optical thin film 12 is formed. An optical element having the same shape as the optical element 11 of the embodiment is manufactured. Therefore, the process of cutting out the protrusion can be omitted.

  According to the present embodiment, the coating guide surfaces 44 c, 44 c, 43 c are provided in the thin film deposition apparatus 40, and the deposition target 28 is held by the fixed holding unit 44 and the moving holding unit 43, so that these The application guide surfaces 44c, 44c, and 43c can be provided on the outer edge of the film formation surface. For this reason, the coating guide surface can be provided before the film-forming body 28 is rotated without providing the protrusion. Thereby, similarly to the first embodiment, it is possible to easily reduce the film thickness variation due to the retention of the thin film forming material in the outer edge portion of the film formation surface.

In the above description of each embodiment and each modification, an example in which the film formation surface of the film formation body is a convex surface or a flat surface has been described. However, for example, a concave surface or the like can be appropriately formed by a wet process. The shape of the deposition surface can be adopted.
Therefore, in addition to the shape of the convex lens described above, shapes such as a biconvex lens, a biconcave lens, a concave lens, and a meniscus lens can be employed as the optical element.

In the description of each of the embodiments and the modifications, the example of the antireflection film that improves the transmittance in the visible region has been described as an example of the thin film. An appropriate thin film that changes optical characteristics such as reflectance, transmittance, and polarization characteristics of the surface can be employed. Examples thereof include an antireflection film, a reflection film, a semi-transmission film, a wavelength selection film, a polarizing film, and a light absorption film.
Examples of other types of thin films include thin films that change the mechanical, physical, and electrical characteristics of the film formation surface and that require high-precision film thickness control. Can do. Examples of such a thin film include a hard coat film, an antistatic film, a conductive film, a water repellent film, a film repellent oil, etc. used on an optical surface that transmits and reflects light functionally in an optical element. Can be mentioned.
Further, the thin film is not limited to a single layer, and a plurality of layers may be provided. In the case of providing a plurality of layers, the steps of curing each layer and then spreading the thin film forming material on the cured thin film and then curing and stacking the thin films may be repeated.

  In the description of each of the embodiments and the modifications described above, the case where the film formation target can be used as an optical element made of a lens or a transparent parallel plate has been described. However, the thin film is a reflective film. Alternatively, it may be an optical element used as a mirror, or in the case where the thin film is a wavelength selection film or a polarizing film, it may be a film formation target that can produce an optical element used as a prism.

Further, in the description of each of the embodiments and the modifications described above, when the coating guide surface extends in the radial direction from the outer edge portion of the film formation surface, a circle is formed on the entire circumference of the outer edge portion of the film formation surface. Although explained in the case of being provided in an annular shape, the extending direction and shape of the coating guide surface can be extended as long as an excessive thin film forming material can be guided outward from the outer edge of the film forming surface. Direction and shape can be adopted.
For example, a spiral spiral shape or a trapezoidal shape in which the width in the circumferential direction widens from the inner side to the outer side in the radial direction may be used.

  In the description of each of the embodiments and the modifications described above, the example in which the film formation body is used for an optical element has been described. However, the film formation body is limited to the shape and material used for the optical element. Not.

In the second embodiment, the example in which the film formation target after film formation is used as an optical element has been described. However, the film formation target after the film formation in the first embodiment and each modification example is described. Also in the film-formed body, for example, the film-formed body 10 that does not cut out the protrusions 10B and the like may be used as it is as an optical element.
At this time, for example, in the optical element having a shape in which the protrusion 10B or the like is left, the protrusion 10B or the like can be used as a component shape for positioning or preventing rotation of the optical element.
Further, in the optical element having the shape in which the projection 27B of the film-formed body 27 of the eighth modification is left, the projection 27B can be used as a flat mounting edge of the optical element.

In the description of each of the embodiments and the modifications described above, the thin film forming material that has reached the end of the application guide surface is scattered by centrifugal force. In the case where there is no possibility that the film flows back to the film forming surface, the thin film forming material may not be scattered from the coating guide surface.
As an example of the case where the thin film forming material does not flow backward, for example, since the area of the coating guide surface is sufficiently large, even if excessive thin film forming material is deposited on the coating guide surface, a thick part is not formed, or thin film formation Examples include a case where fluidity is lowered in a state where a thick portion is formed because the material is quickly dried.

  In the description of the eighth modification, the example in which the projection 27B is cut off to manufacture the optical element 38 has been described. However, the projection 27B is located at a position corresponding to the outer peripheral portion of the edge flat surface 10b. By cutting, a convex flat lens with a flat edge having the same shape as the optical element 11 may be manufactured.

In the description of the seventh modification, the application guide surface 25c is described as an example of a rotationally symmetric surface with respect to the optical axis O. However, the application guide surface 25c is not limited to a rotationally symmetric surface. .
For example, the cross-sectional shape along the circumferential direction of the application guide surface 25c is a spherical convex surface along the convex surface portion 24a in the vicinity of the convex surface portion 24a, and from the convex surface portion 24a toward the radially outer end of the protrusion 25B. The sectional shape along the circumferential direction may be a concave shape by gradually changing the curvature as the distance increases.
In this case, since a groove portion that opens upward and extends radially outward is formed on the application guide surface 25c, the thin film forming material 9 is smoothly guided in the radial direction without scattering in the circumferential direction.
Further, since the thin film forming material 9 can be stored in the groove-shaped portion of the application guide surface 25c, even if the thin film forming material 9 is not scattered by centrifugal force, the excessive thin film forming material 9 is stopped on the application guide surface 25c. In addition, it can be prevented from flowing back to the film formation surface side.

  In addition, all the components described in the above embodiments and modifications can be implemented by being appropriately combined or deleted within the scope of the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1, 40 Thin film formation apparatus 2, 41 Holding jig 2a Upper surface 2c Holding hole part 5 Drive motor 7 Material dripping part 9 Thin film formation material 9A Coating film 9B Excess film part 9C Scattering body 9a Coating film front-end | tip 9b Thick part 10, 20, 21, 22, 23, 24, 25, 26, 27, 28 Deposition target body 10A, 23A, 24A, 27A Deposition target body 10B, 20B, 21B, 22B, 24B, 25B, 26B, 27B Protrusion 10F Edge flat part 10L Lens part 10a, 24a Convex surface part (deposition surface)
10b Edge flat surface (deposition surface)
10c, 20c, 21c, 22c, 24c, 25c, 26c, 44c, 45c Coating guide surface 10e, 27e Side surface portion 11, 33, 34, 36, 38 Optical element 12 Optical thin film (thin film)
22e Step 23a Flat surface (film formation surface)
23b Effective application area 24a Convex surface (film formation surface)
24b Lens effective area O Optical axis P Center axis

Claims (7)

A thin film forming material is formed by supplying a liquid thin film forming material to a film forming surface on the film forming body and spreading the thin film forming material on the film forming surface by rotating the film forming body. A membrane method,
Before rotating the deposition target,
A thin film forming method, characterized in that a coating guide surface for guiding the thin film forming material further outward from an outer edge portion of the film forming surface is provided. The film-deposited body is formed by resin molding into a shape having a film-deposited body main body including the film-deposited surface and a protrusion that protrudes outward from the outer peripheral portion of the film-deposited body. And
The thin film deposition method according to claim 1, wherein the coating guide surface is provided at a position adjacent to the deposition target surface on the protrusion. 3. The method of forming a thin film according to claim 2, wherein after the film formation, the protrusion is cut out from the body of the film formation target. 4. The thin film forming method according to claim 2, wherein the protrusion includes a gate portion of the resin molding. The application guide surface is a flat surface or a curved surface,
When the target application thickness of the thin film forming material is h, the height of the application guide surface with respect to the film formation surface at the boundary between the application guide surface and the film formation surface is 0 or more and h or less. The thin film deposition method according to claim 1, wherein the thin film deposition method is characterized. 6. The thin film forming material that reaches the outer edge of the film formation surface is scattered through the application guide surface by a centrifugal force when the film formation object is rotated. The thin film formation method according to item.   An optical element manufacturing method for manufacturing an optical element by forming a thin film on the film-forming body using the thin film forming method according to claim 1.

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