WO2016060199A1

WO2016060199A1 - Lens manufacturing method

Info

Publication number: WO2016060199A1
Application number: PCT/JP2015/079154
Authority: WO
Inventors: 裕貴七海; 朋一梅澤; 伸輔高橋
Original assignee: 富士フイルム株式会社
Priority date: 2014-10-16
Filing date: 2015-10-15
Publication date: 2016-04-21
Also published as: JP2016078328A; JP6353341B2

Abstract

The purpose of the present invention is to provide a lens manufacturing method that can accurately position a light-shielding member inside a mold unit without providing a positioning section on the light-shielding member or providing a dedicated positioning member independent of the light-shielding member. A positioning section for positioning a diaphragm plate (light-shielding member) is provided on a preform formed from a lens material. The positioning section engages with the diaphragm aperture of the diaphragm plate and positions the diaphragm plate. The diaphragm plate is pre-assembled to the preform. In this state, the preform is charged in the mold unit. The preform is heated and is compression molded by the mold unit.

Description

Lens manufacturing method

The present invention relates to a method of manufacturing a lens including a light shielding member.

For example, as described in JP-A-2009-080500, a lens including a light shielding member is known. Japanese Patent Laid-Open No. 2009-080500 discloses a lens with a stop plate in which a stop plate having a stop opening formed therein is included as a light shielding member. A lens with a diaphragm is used, for example, in a compact imaging device or a camera (paragraph 0001). The diaphragm-equipped lens is manufactured by injection molding (paragraphs 0015 and 0016). Specifically, it is manufactured by a so-called insert molding method in which a transparent resin is injected into the mold unit in a state in which the squeezing plate is inserted into the mold unit for injection molding.

The above-described diaphragm plate is provided on a first region having a diaphragm function and a diaphragm function of the periphery thereof and on the outer periphery of the first region, and a second region for positioning the diaphragm plate in the mold unit (hereinafter referred to as positioning Section) and (section 0013). The positioning portions extend outward in two directions in the left and right of the first area like an earlobe, and through holes for inserting positioning pins are formed in each positioning portion. Providing the positioning portion enables accurate positioning of the diaphragm with respect to the optical axis of the lens.

However, when manufacturing a lens with a diaphragm plate by injection molding, there is a problem that it is necessary to separately provide a positioning portion on the diaphragm plate as described in JP-A-2009-080500. In injection molding, the injection pressure of the resin into the mold unit is large. Therefore, when the positioning plate is not provided on the diaphragm plate, there is a possibility that the displacement of the diaphragm plate may occur due to the injection of the resin, so the positioning plate is required to accurately position the diaphragm plate. . Even when the positioning plate is not provided on the diaphragm plate, a dedicated positioning member is required to accurately position the diaphragm in the mold unit. If so, the number of assembly steps and time will increase.

The present invention provides a method of manufacturing a lens capable of accurately positioning a light shielding member in a mold unit without providing a positioning portion in the light shielding member or providing a dedicated positioning member independent of the light shielding member. The purpose is to

In order to achieve the above object, the lens manufacturing method of the present invention has a temporary assembling step, a preform charging step, and a compression molding step in the lens manufacturing method in which the light shielding member is included. In the temporary assembling step, the light shielding member is temporarily assembled by engagement with the positioning portion with respect to a preform which is formed in advance using a lens material in a shape having a positioning portion for positioning the light shielding member. In the preform charging step, the preform on which the light shielding member is temporarily assembled is charged into the mold unit. In the compression molding process, the preform is compression-molded into a lens shape in which a light shielding member is included by heating a mold unit into which the preform is charged.

The light blocking member is preferably an apertured light blocking member in which an opening is formed. The positioning portion is preferably convex and engaged with the opening.

The light shielding member with an opening is a diaphragm plate in which a diaphragm opening is formed as an opening in a flat light shielding plate, and the diaphragm is arranged in the lens in a state where the center of the diaphragm opening coincides with the optical axis of the lens Is preferred.

The preform has a disk-shaped main body having a circular horizontal cross section orthogonal to the optical axis, and the convex positioning portion is formed at the center in the horizontal direction in the main body, and It is preferred to engage.

The preform is preferably a single piece having a volume covering the entire material for molding the lens.

The preform is composed of a plurality of members including a first preform and a second preform, and the second preform has a convex positioning portion engaged with the diaphragm plate, and the first preform is It is preferable to be joined with the second preform in a state in which the throttling plate is sandwiched between the second preform and the second preform.

In the second preform, the convex positioning portion is joined to the first preform and has a cemented surface that functions as a lens surface, and the cemented lens is formed by joining the first preform and the second preform. Preferably it is formed.

It is preferable that the light shielding member has a reflection preventing structure by the unevenness formed on the surface.

In the light shielding member, the unevenness includes two types of unevenness: a first unevenness and a second unevenness having an arrangement period longer than an average arrangement cycle of the first unevenness, and the first unevenness is on the second unevenness Preferably, it is formed.

It is preferable that an arrangement | sequence period is below the wavelength of the light which becomes reflection prevention object for 1st unevenness | corrugation.

According to the present invention, accurate positioning of the light shielding member in the mold unit can be performed without providing the positioning portion in the light shielding member or providing a dedicated positioning member independent of the light shielding member.

It is a whole perspective view of the lens of 1st Embodiment. It is sectional drawing of the lens of FIG. It is a top view of the lens of FIG. It is explanatory drawing of a lens manufacturing apparatus. It is explanatory drawing of preform. It is explanatory drawing of the manufacturing method of the lens of FIG. It is sectional drawing of the cemented lens of 2nd Embodiment. It is explanatory drawing of the preform of the cemented lens of FIG. It is explanatory drawing of the manufacturing method of the lens of FIG. It is explanatory drawing of the preform of 3rd Embodiment. It is a perspective view of the preform of FIG. It is explanatory drawing of the reflection preventing structure of the surface of an aperture plate.

First Embodiment
The lens 10 shown in FIGS. 1 to 3 is a lens in which the diaphragm plate 11 is contained. In the lens 10, a lens portion 12 is formed at a central portion including the optical axis LA. The lens unit 12 has, for example,

lens surfaces

13 and 14 respectively corresponding to an incident surface on which light from an object is incident and an exit surface from which incident light is emitted. The

lens surfaces

13 and 14 have refractive power for incident light. The

lens surfaces

13 and 14 have, for example, a convex shape on both surfaces, and the lens unit 12 functions as a convex lens. A flange portion 16 is formed around the

lens surfaces

13 and 14. The

lens surfaces

13 and 14 may be spherical or aspheric. The lens unit 12 is not limited to a convex lens, and may be, for example, a concave lens.

As is well known, the diaphragm plate 11 has a diaphragm opening 17 formed at the center of a flat circular light shielding plate, and the periphery of the diaphragm opening 17 functions as a light shielding portion 18. Of the incident light incident on the lens 10 from the lens surface 13, only the light passing through the diaphragm opening 17 is emitted from the lens surface 14, and the remaining light is blocked by the light blocking portion 18. The diaphragm plate 11 corresponds to a light shielding member with an opening that has the diaphragm opening 17 as an opening. The diaphragm plate 11 is disposed in the lens 10 in a state of being accurately positioned with respect to the optical axis LA of the lens 10. Specifically, the diaphragm plate 11 is disposed in a state where the center of the diaphragm opening 17 and the optical axis LA coincide with each other. The entire peripheral surface of the diaphragm plate 11 is accommodated in the lens 10, including the side surface portion located at the outer edge.

The lens 10 is manufactured by a lens manufacturing apparatus 21 shown in FIG. The lens manufacturing apparatus 21 manufactures the lens 10 by performing compression molding while heating a lens material such as transparent plastic or glass. The lens manufacturing apparatus 21 includes a mold unit 22, a moving mechanism 23, a heater 24, and a control unit 26. The mold unit 22 has a first mold 27, a second mold 28, and a body mold 29.

The body mold 29 has a circular cross-sectional shape in the horizontal direction orthogonal to the compression direction, and has a guide hole 29A penetrating in the compression direction of the first mold 27 and the second mold. The compression direction is the vertical direction in FIG. The first mold 27 and the second mold 28 are guided by the inner wall of the guide hole 29A and are movable in the compression direction. The first mold 27 and the second mold 28 form the lens 10 by compression-molding the preform 31 in the body mold 29. The preform 31 is a prototype of the lens 10 previously formed of a lens material, and is formed in a shape suitable for compression molding of the lens 10. The preform 31 is formed, for example, by injection molding when the lens material is plastic.

In the first mold 27 and the second mold 28,

concave transfer surfaces

27A and 28A for forming the convex lens surfaces 13 and 14 of the lens 10 are formed on mutually opposing surfaces, respectively. There is.

The moving mechanism 23 moves the first mold 27 and the second mold 28 in the compression direction. When the preform 31 is inserted into the barrel 29, the first mold 27 is moved upward and retracted from the barrel 29. The heater 24 heats the mold unit 22 to heat the preform 31 in the body die 29. The moving mechanism 23 and the heater 24 are controlled by the control unit 26. The control unit 26 controls the amount of heat generation of the heater 24 to adjust the temperature in the barrel 29.

As shown in FIG. 5, the preform 31 has a disk-shaped main body 32 having a circular horizontal cross section (horizontal cross section) orthogonal to the optical axis LA, and a convex positioning for positioning the diaphragm 11. And a part 33. The positioning portion 33 is formed integrally with the main body portion 32, and the preform 31 is formed in advance in a shape having the positioning portion 33.

In the main body portion 32, the upper surface 32A and the lower surface 32B of the main body portion 32 are formed in parallel planes, and the planar shape of the

upper surfaces

32A and 32B is circular. The positioning portion 33 is a convex that protrudes in a cylindrical shape from the upper surface 32 </ b> A of the main body portion 32.

The preform 31 is a prototype for molding the lens 10, and thus has a volume covering the lens material for molding the lens 10 as a whole including the positioning portion 33. The outer diameter of the main body portion 32 is substantially the same size as the inner diameter of the body mold 29 of the mold unit 22. Therefore, in the mold unit 22, the preform 31 is positioned in the horizontal direction orthogonal to the compression direction (the direction of the optical axis LA) by the engagement of the outer periphery of the main body 32 and the inner wall of the barrel 29.

The horizontal positioning of the preform 31 in the mold unit 22 can be performed by a method other than the engagement between the outer periphery of the main body 32 and the inner wall of the barrel 29. For example, in the same manner as the embodiment of FIG. 9 described later, a convex portion conforming to the shape of the concave transfer surface 28A of the second mold 28 is formed on the lower surface 32A of the main body portion 32. Horizontal positioning may be performed by engagement. When the transfer surface 28A is convex, a recess is formed on the lower surface 32A, and the transfer surface 28A and the lower surface 32A are engaged to perform positioning.

The positioning portion 33 substantially matches the outer diameter of the positioning portion 33 and the inner diameter of the diaphragm opening 17. Further, the positioning portion 33 is formed at the center in the horizontal direction on the upper surface 32A of the main body portion 32. More specifically, the positioning portion 33 is formed at a position where the central axis of the positioning portion 33 coincides with the optical axis LA. The diaphragm plate 11 can be temporarily assembled on the preform 31 by inserting the positioning portion 33 into the diaphragm opening 17. In the temporarily assembled state, the diaphragm plate 11 is placed on the upper surface 32 A of the main body 32. By this temporary assembly, the diaphragm plate 11 is positioned in a state where the center of the diaphragm opening 17 and the position of the optical axis LA located at the center of the main body 32 (the center of the circular upper surface 42A) coincide.

A method of manufacturing the lens 10 will be described with reference to FIG. First, the positioning plate 33 of the preform 31 is inserted through the diaphragm opening 17 to temporarily assemble the diaphragm plate 11 on the preform 31 (temporary assembly process). By this temporary assembly, the diaphragm plate 11 is accurately positioned at a position where the center of the diaphragm opening 17 coincides with the optical axis LA.

Next, the preform 31 preformed is put into the barrel 29 of the mold unit 22 and placed on the second mold 28 (preform charging step). The introduction of the preform 31 is performed using a suction arm (not shown) or the like. The preform 31 is positioned in the horizontal direction by the engagement of the main body 32 and the body mold 29.

When the preform 31 is introduced into the mold unit 22, compression molding is performed on the introduced preform 31. The compression molding process is composed of three processes, a heating process, a molding process, and a pressure holding and cooling process. First, the control unit 26 drives the heater 24 to heat the preform 31 (heating step). The control unit 26 controls the heater 24 to adjust the temperature in the mold unit 22 and heat the preform 31 to the glass transition temperature Tg. Although the preform 31 is softened at the glass transition temperature Tg, the shape of the positioning portion 33 and the like is maintained. Therefore, even after heating, the positioning action of the diaphragm plate 11 by the positioning portion 33 functions effectively.

When the preform 31 is heated, it enters a molding process. In the molding process, first, the control unit 26 controls the moving mechanism 23 to cause the first mold 27 to enter the barrel 29. Then, the moving mechanism 23 moves the first mold 27 toward the second mold 28 in the barrel mold 29. The preform 31 in a state of being softened by heating is compressed by applying pressure by being sandwiched between the transfer surface 27A of the first mold 27 and the transfer surface 28A of the second mold 28 (molding process) . Thereafter, the compressed preform 31 is cooled while maintaining the pressure. By cooling while maintaining the compressed state, the formed shape is fixed (holding pressure cooling step). The preform 31 is formed into a lens shape by such a compression molding process.

The positioning portion 33 of the preform 31 spreads toward the outer edge of the main body portion 32 while being crushed by the transfer surface 27A. Thereby, the lens material in which a part of the preform 31 is melted flows into the upper side of the diaphragm plate 11, the whole diaphragm plate 11 is covered, and the diaphragm plate 11 is included in the lens material. Since the positioning portion 33 is engaged with the diaphragm opening 17 of the diaphragm plate 11, the lens material in which the positioning portion 33 is melted spreads radially around the diaphragm opening 17. Therefore, the molten lens material easily flows into the entire surface of the diaphragm plate 11, and good formability is secured.

In addition, when the positioning portion 33 is crushed, a part of the main body portion 32 is poured into the recess in which the transfer surface 28A is formed. The lens surfaces 13 and 14 (see FIG. 2) are formed by the transfer surface 27A and the transfer surface 28A, whereby the lens 10 is formed. When the compression molding is completed, the first mold 27 is retracted from the barrel mold 29 after cooling, and the lens 10 is taken out.

In the mold unit 22, the preform 31 is positioned in the horizontal direction by engagement with the cylinder mold 29. On the other hand, the diaphragm plate 11 is temporarily assembled on the positioning portion 33 of the preform 31 so that the top surface 32A of the main body portion 32 of the preform 31 is positioned in the horizontal direction which is the lateral direction. Therefore, even if an external force acts on the diaphragm plate 11 and the preform 31 in the mold unit 22, the positional deviation of the diaphragm plate 11 with respect to the preform 31 does not occur. The diaphragm plate 11 is disposed in the lens 10 after molding in a state of being accurately positioned in the temporary assembly.

Moreover, since the positioning part 33 is provided in the preform 31, there is no need to provide the positioning part in the aperture plate 11 as in the prior art. Therefore, the degree of freedom in design concerning the shape of the diaphragm plate 11 contained in the lens 10 can be increased. In addition, it is not necessary to provide a dedicated positioning member independent of the diaphragm plate 11. Therefore, in the manufacturing process of the lens 10, the process of arranging a dedicated positioning member in the mold unit 22 and the process of engaging the dedicated positioning member and the preform 31 are eliminated, so the manufacturing process is made more efficient. it can. Further, in compression molding, there is no injection pressure of the material as in injection molding, so it is also difficult to position the drawing plate 11 accordingly. Further, since the positioning portion 33 is integrally molded with the preform 31 and consumed as the material of the lens 10, there is no waste of material. In addition, since the lens 10 is manufactured from one preform 31, the number of steps is reduced and the manufacturing efficiency is high.

In the above embodiment, the upper surface 32A and the lower surface 32B of the main body portion 32 of the preform 31 have been described as flat surfaces, but at least one of the upper surface 32A and the lower surface 32B may be formed as a curved surface. For example, the lower surface 32B may be formed as a spherical or aspheric lens surface. In this case, since the lens surface is formed on the lower surface 32B when the preform 31 is formed, the upper surface 32A is formed at the time of compression molding.

In the present embodiment, the example has been described in which the diaphragm plate 11 is positioned by engaging the diaphragm opening 17 of the diaphragm plate 11 and the cylindrical convex positioning portion 33 provided in the preform. The shape of the positioning portion may be another shape. For example, the positioning portion 33 may be prismatic instead of cylindrical. If the cross-sectional shape of the prismatic column is a regular polygon, accurate positioning of the diaphragm plate 11 can be performed by matching the diameter of the circumscribed circle of the regular polygon diameter with the diameter of the diaphragm opening 17. The height of the positioning portion in the direction of the optical axis LA may be any height that allows engagement with the diaphragm opening 17, and may be equal to or less than the thickness of the diaphragm opening 17. Of course, in order to engage more reliably, it is preferable that the height of the positioning portion in the optical axis LA direction has a height equal to or greater than the thickness of the diaphragm opening 17.

"2nd Embodiment"
In the second embodiment shown in FIGS. 7 to 9, the cemented lens 43 is a cemented lens in which two

lens portions

41 and 42 are combined. As shown in FIG. 8, the cemented lens 43 is manufactured from a plurality of members of the first preform 46 and the second preform 47.

In FIG. 7, in the

lens portions

41 and 42, one lens surfaces 41A and 42A are exposed, and the

other lens surfaces

41B and 42B face each other and are joined. Hereinafter, the

other lens surfaces

41B and 42B are referred to as cemented

surfaces

41B and 42B, respectively. Inside the cemented lens 43, a boundary between the cemented

surfaces

41B and 42B of the

lens portions

41 and 42 is formed. Further, in the cemented lens 43, the diaphragm plate 11 is contained. The inside diameter of the diaphragm opening 17 of the diaphragm plate 11 is substantially the same size as the outside diameter of the

joint surfaces

41B and 42B. In the cemented lens 43, the diaphragm plate 11 is disposed such that the cemented surfaces 41 B and 42 B are exposed from the diaphragm opening 17.

As shown in FIG. 8, a lens surface 41 </ b> A and a bonding surface 41 </ b> B are formed on the first preform 46. The bonding surface 41B also functions as a lens surface. The lens surface 41A is a convex surface, and the joint surface 41B is a concave surface. A lens surface 42A and a bonding surface 42B are formed on the second preform 47. The bonding surface 42B also functions as a lens surface. The lens surface 42A and the cementing surface 42B are both convex. When the lens material is plastic, the first preform 46 and the second preform 47 are formed, for example, by injection molding.

In the second preform 47, the protruding portion 48 in which the joint surface 42B is formed functions as a convex positioning portion for positioning the diaphragm plate 11. The diaphragm plate 11 is temporarily assembled to the second preform 47 by the diaphragm opening 17 engaging with the raised portion 48. The outer diameter of the joint surface 42B of the raised portion 48 and the inner diameter of the throttle opening 17 substantially coincide with each other. The center of the cemented surface 42 B coincides with the optical axis LA of the cemented lens 43. Therefore, when the diaphragm plate 11 is temporarily assembled to the second preform 47, the diaphragm plate 11 is positioned on the second preform 47 in a state where the center of the diaphragm opening 17 and the optical axis LA coincide with each other.

As shown in FIG. 9, in the method of manufacturing the cemented lens 43, first, the diaphragm plate 11 is temporarily assembled on the second preform 47 and is introduced into the mold unit 22. Then, the first preform 46 is put into the mold unit 22 and arranged to overlap on the second preform 47. In this state, the first preform 46 and the second preform 47 are heated to the glass transition temperature Tg by the heater 24.

After heating, the first preform 46 and the second preform 47 are compression molded by the first mold 27 and the second mold 28. The cemented lens 43 is molded by compression molding. The first preform 46 is joined to the second preform 47 in a state in which the diaphragm plate 11 is sandwiched between the first preform 46 and the second preform 47. After compression molding, the molded cemented lens 43 is taken out of the mold unit 22. In such a manufacturing process, since the diaphragm plate 11 is positioned by the engagement of the diaphragm opening 17 and the protruding portion 48 of the second preform 47, the diaphragm plate 11 may be provided with a positioning portion or There is no need to provide a dedicated positioning member independent of the plate 11. Thereby, the degree of freedom in design of the diaphragm plate 11 is improved, and the manufacturing process is also made efficient.

In the second embodiment, an example in which two preforms are used is described, but the number of preforms may be three or more. The use of multiple preforms makes it possible to produce lenses of complex construction.

"3rd Embodiment"
Further, as in the third embodiment shown in FIGS. 10 and 11, the diaphragm plate 11 may be positioned by engaging the outer edge of the diaphragm plate 11 with the positioning portion 51B provided on the preform 51. The preform 51 has a disk-shaped main body 51A, and an annular positioning portion 51B erected on the outer peripheral edge of the main body 51A. The outer diameter of the diaphragm plate 11 matches the inner diameter of the positioning portion 51B, and when the diaphragm plate 11 is accommodated in the positioning portion 51B, the diaphragm plate 11 is engaged by the outer edge of the diaphragm plate 11 and the inner wall of the positioning portion 51B. Is positioned.

However, when the diaphragm plate 11 is positioned, as in the first and second embodiments, the diaphragm plate 11 is engaged by the engagement between the positioning portion formed at the center of the preform and the diaphragm opening 17. It is preferable to position the The reason is as follows. In the diaphragm plate 11, since the diaphragm opening 17 is a functionally important part, in general, the inside diameter of the diaphragm opening 17 is higher in dimensional accuracy than the outside diameter of the diaphragm plate 11. Therefore, positioning can be performed with higher accuracy if the diaphragm opening 17 is engaged with the positioning portion rather than the outer edge of the diaphragm plate 11. Further, in order to stretch the melted lens material over the entire surface of the diaphragm plate 11 temporarily assembled on the preform, the lens material is more likely to enter in the direction from the center to the outside than in the direction from the outside to the center. Also in terms of such moldability, it is more advantageous to form the positioning portion in the central portion of the preform as in the first and second embodiments.

"4th Embodiment"
Further, as the diaphragm plate 11, as shown in FIG. 12, an anti-reflection structure may be provided on the surface of the light shielding portion 18. The anti-reflection structure includes, for example, two types of first unevenness 56 and second unevenness 57 having different average arrangement periods of unevenness, as described in JP 2009-128522 A, and the first unevenness 56 And it is the 2 layer structure where the 2nd unevenness 57 was layered.

The first unevenness 56 is formed, for example, by arranging a plurality of fine conical projections 56A. The arrangement period of the first unevenness 56 by the protrusions 56A is, for example, equal to or less than the wavelength of the light to be subjected to reflection prevention. When the light to be antireflective is visible light, the arrangement period of the first unevenness 56 is 400 nm or less, where the shortest wavelength of the visible light is 400 nm.

The anti-reflection structure by the fine projections 56A such as the first unevenness 56 is also called a moth-eye structure. The moth-eye structure is formed by arranging a plurality of conical projections 56A having a thin tip and a thick root. In the moth-eye structure, the apparent refractive index changes gradually because the volume ratio of the material of the projections to the medium of light occupying between the adjacent projections gradually changes from the tip to the root of the projections. . Therefore, light incident on the first unevenness 56 is less likely to be reflected or refracted, and is absorbed by the first unevenness 56. Here, the medium of light is a lens material when the moth-eye structure is present in the lens as in this example, and is air when the moth-eye structure is present in the atmosphere outside the lens.

The first unevenness 56 is formed on the second unevenness 57, and the second unevenness 57 functions as a base surface of the first unevenness 56. The second unevenness 57 is formed by the plurality of protrusions 57A. The average arrangement period of the second unevenness 57 by the protrusions 57A is longer than the average arrangement period of the protrusions 56A. For example, it has a wavelength longer than the wavelength of light to be anti-reflection. When the light to be anti-reflection is visible light, if the longest wavelength of visible light is 800 nm, the average arrangement period of the projections 57A is 800 nm or more. More specifically, it has a micro-order alignment period of 1 μm (1000 nm) or more. The second unevenness 57 scatters the light which can not be absorbed by the first unevenness 56 to obtain an antireflection effect.

Here, the average arrangement cycle of the first unevenness 56 and the second unevenness 57 is obtained by observing the cross section of the unevenness with a scanning electron microscope (SEM: Scanning Electron Microscope), or between the peaks (Crest) of adjacent unevenness or The distance between the valleys (Root) is measured at 10 points, and the average value thereof is taken.

In the case where the diaphragm plate 11 has such a reflection preventing structure, if the surface of the diaphragm plate 11 is exposed to the outside, it is difficult to handle the diaphragm plate 11 so as not to damage the surface antireflection structure. When the diaphragm plate 11 is included as in the lens 10 and the cemented lens 43, the surface of the diaphragm plate 11 is not directly exposed to the outside, so that the handleability of the diaphragm plate 11 is improved.

In the fourth embodiment, an example in which the anti-reflection structure having two types of unevenness is described has been described, but the anti-reflection structure may be configured by only the first unevenness, for example.

In each of the above-described embodiments, although the diaphragm plate has been described as an example of the light shielding member, the light shielding member may not be the diaphragm plate, or may be a light shielding member having no opening.

The present invention is not limited to the above embodiments, and it goes without saying that various configurations can be adopted without departing from the scope of the present invention. For example, the above-described various embodiments and various modifications may be combined as appropriate.

Claims

In a method of manufacturing a lens in which a light shielding member is included,
A temporary assembling step of temporarily assembling the light shielding member by engaging the positioning portion with a preform formed in advance using a lens material in a shape having a positioning portion for positioning the light shielding member; ,
A preform charging step of charging the preform, in which the light shielding member is temporarily assembled, into a mold unit;
A compression molding step of heating the preform placed in the mold unit and compressing it in a heated state to form a lens shape in which the light shielding member is contained and fix it by cooling;
A manufacturing method of a lens characterized by having.
The method according to claim 1, wherein the light blocking member is a light blocking member with an opening in which the opening is formed.
The method according to claim 2, wherein the positioning portion is convex and engages with the opening.
The light shielding member with an opening is a diaphragm in which a diaphragm is formed as the opening in a flat light shielding plate,
The method according to claim 3, wherein the diaphragm plate is disposed in the lens in a state in which the center of the diaphragm aperture coincides with the optical axis of the lens.
The preform has a disk-shaped main body having a circular horizontal cross section orthogonal to the optical axis,
The lens manufacturing method according to claim 4, wherein the convex positioning portion is formed at the center in the horizontal direction in the main body portion, and engages with the diaphragm opening.
The method according to claim 5, wherein the preform is a single member having a volume covering an entire material for molding the lens.
The preform is composed of a plurality of members including a first preform and a second preform,
The second preform has the convex positioning portion engaged with the diaphragm plate,
The lens manufacturing method according to claim 5, wherein the first preform is joined to the second preform in a state in which the diaphragm plate is sandwiched between the first preform and the second preform.
In the second preform, the convex positioning portion is joined to the first preform, and has a cemented surface that functions as a lens surface,
The method according to claim 7, wherein a cemented lens is formed by joining the first preform and the second preform.
The method for manufacturing a lens according to claim 1, wherein the light shielding member has an anti-reflection structure by unevenness formed on the surface.
The asperities include two types of asperities, a first asperity and a second asperity having an arrangement period longer than an average arrangement period of the first asperities,
The method according to claim 9, wherein the first unevenness is formed on the second unevenness.
The method according to claim 10, wherein the first unevenness is equal to or less than the wavelength of light to be subjected to the reflection prevention of the arrangement period.