Optical instruments, methods for manufacturing optical instruments

Abstract

To provide a lens barrel part that is formed of carbon fiber reinforced resin, is excellent in strength including impact resistance performance, is reduced in size or weight and thickness, and has high-quality appearance.SOLUTION: Carbon fiber braid layers 3 and 5 assembled in a cylindrical shape and endlessly in a circumferential direction of the cylindrical shape, and a one-directional prepreg sheet layer 4 formed of carbon fiber oriented in one direction, are solidified and coupled to each other with thermoplastic resin to form a cylindrical body 1. The braid layer 3 and 5 are braided in an endless cylindrical shape on a mandrel in a circumferential direction of the mandrel, with the one-directional prepreg sheet layer 4 located therebetween.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a lens barrel part composed of a carbon fiber reinforced resin, an optical device, and a method for manufacturing the lens barrel part.

Background Art

[0002] Conventionally, interchangeable lenses of cameras, for example, telephoto lenses with a focal length exceeding 300 mm are large-sized and some reach the order of several kilograms in weight. Even for optical devices with such a focal length range, lightweight and high-strength products are desired from the viewpoints of ease of carrying and improvement in operability during shooting.

[0003] Conventionally, for the material of the lens barrel of this type of large optical device, aluminum alloy or magnesium alloy has been used from the viewpoint of impact resistance. Also, for the hood attached to the lens, aluminum alloy has been adopted for its material from the viewpoint of impact resistance. However, even though this type of metal material belongs to light metals, there is a limit to weight reduction.

[0004] Therefore, in recent years, it has been considered to manufacture a lens barrel and a hood using a carbon fiber reinforced resin (CFRP) in which carbon fiber is impregnated with a thermosetting resin such as epoxy. When manufacturing a lens barrel part using the carbon fiber reinforced resin (CFRP), for example, the shape is formed by a manufacturing method called a sheet winding method (SW method) in which a unidirectional prepreg sheet in which carbon fibers are aligned in one direction is wound around a cylindrical mold called a mandrel. Then, the carbon fiber is impregnated and cured with a thermosetting resin such as epoxy in an autoclave or the like.

[0005] However, differences in the alignment direction and layer combination of carbon fibers resulted in variations in strength, sometimes failing to achieve the desired impact resistance. To address this problem, a configuration has been proposed in which unidirectional prepreg sheets are laminated in single or multiple layers in both the axial and circumferential directions of the lens barrel to create a unified structure. In this process, the final circumferential unidirectional prepreg sheet is wrapped around the outside of the axial unidirectional prepreg sheet to obtain impact resistance (see Patent Document 1 below). [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 4813619 [Overview of the project] [Problems that the invention aims to solve]

[0007] As described above, in the SW method, in which a unidirectional prepreg sheet is wound around a mandrel, seams in the sheet inevitably occur during the manufacturing process, and these seams can lead to variations in strength, such as a decrease in impact resistance. Therefore, one possible solution is to laminate multiple layers of unidirectional prepreg sheets wound around the mandrel, and to shift the position of the seams. However, this would necessitate compensating for the strength degradation caused by the seams by increasing the number of layers, raising concerns that the weight reduction effect would be reduced. Furthermore, the presence of seams could lead to differences in curing shrinkage between the seam area and the rest of the sheet during the subsequent sintering process, which involves curing the impregnating resin and forming the shape, potentially resulting in an inability to achieve perfect roundness in the lens barrel. In addition, if the impregnating resin is a thermosetting resin such as epoxy with a long curing time, there are concerns about a decrease in productivity.

[0008] The object of the present invention is to provide a lens barrel component made of carbon fiber reinforced resin, which has excellent strength such as impact resistance, is small or thin and lightweight, and has a high-quality appearance. [Means for solving the problem]

[0009] A first aspect of the present invention is an optical instrument including an optical element and a lens barrel for holding or adjusting the optical element, comprising a cylindrical body which is a lens barrel component, the cylindrical body comprising a cylindrical first carbon fiber layer and a cylindrical second carbon fiber layer located on the outer circumference side of the cylindrical body relative to the first carbon fiber layer, A third carbon fiber layer is provided between the first carbon fiber layer and the second carbon fiber layer, The first carbon fiber layer is a braided layer provided in the circumferential direction of the tubular body, wherein a plurality of carbon fibers of the first carbon fiber layer are intersected and assembled into a tubular shape, and the braided layer is provided in the circumferential direction of the tubular body in an endless manner. The plurality of carbon fibers in the first carbon fiber layer include carbon fibers oriented in a first direction inclined with respect to the axial direction of the cylindrical body, and carbon fibers oriented in a second direction inclined with respect to the axial direction of the cylindrical body. The first carbon fiber layer is impregnated with resin, and the second carbon fiber layer is a braided layer in which a plurality of carbon fibers of the second carbon fiber layer are intersected and woven into a tubular shape, and is provided in an endless manner in the circumferential direction of the tubular body, and the second carbon fiber layer is impregnated with resin Ori , The first carbon fiber layer and the third carbon fiber layer are fixed together with resin, and the second carbon fiber layer and the third carbon fiber layer are fixed together with resin. This is an optical instrument characterized by the following features. A second aspect of the present invention is a method for manufacturing an optical instrument including an optical element and a lens barrel for holding or adjusting the optical element, wherein the manufacturing step of a cylindrical body which is a lens barrel component of the optical instrument is a step of forming a first carbon fiber layer impregnated with a first thermoplastic resin on a mandrel, a step of forming a second carbon fiber layer impregnated with a second thermoplastic resin on the first carbon fiber layer on the mandrel, and a step of heating the first thermoplastic resin and the second thermoplastic resin to fix the first carbon fiber layer and the second carbon fiber layer. The manufacturing method is characterized by comprising, in the step of forming the first carbon fiber layer, the first carbon fiber layer is a braided layer in which a plurality of carbon fibers of the first carbon fiber layer are assembled in a tubular shape at an inclination with respect to the axial direction of the tubular body and provided to be endless in the circumferential direction of the tubular body, and in the step of forming the second carbon fiber layer, the second carbon fiber layer is a braided layer in which a plurality of carbon fibers of the second carbon fiber layer are assembled in a tubular shape at an inclination with respect to the axial direction of the tubular body and provided to be endless in the circumferential direction of the tubular body. [Effects of the Invention]

[0010] According to the above configuration, it is possible to provide a telescope tube component made of carbon fiber reinforced resin, which has excellent strength such as impact resistance, is small or thin and lightweight, and has a high-quality appearance. [Brief explanation of the drawing]

[0011] [Figure 1] The structure of a cylindrical body according to an embodiment of the present invention is shown, where (a) is a plan view of the cylindrical body and (b) is a cross-sectional view of the cylindrical body. [Figure 2] This is a perspective view showing a braiding device according to an embodiment of the present invention. [Figure 3] The structure of a cylindrical body according to an embodiment of the present invention is shown, where (a) is a plan view of the cylindrical body and (b) is a cross-sectional view of the cylindrical body. [Figure 4] The following diagrams illustrate different structures of the cylindrical body according to the present invention: (a) is a plan view of the cylindrical body, (b) is a cross-sectional view of the cylindrical body, and (c) is an enlarged cross-sectional view of a part of the cylindrical body. [Figure 5] Further different structures of the cylindrical body according to the embodiment of the present invention are shown, where (a) is a plan view of the cylindrical body, (b) is a cross-sectional view of the cylindrical body, and (c) is an enlarged cross-sectional view of a part of the cylindrical body. [Figure 6] (a) to (d) are explanatory diagrams showing the insert molding process for a cylindrical body according to an embodiment of the present invention. [Figure 7] Further different structures of the cylindrical body according to the embodiment of the present invention are shown, where (a) is a plan view of the cylindrical body, (b) is a cross-sectional view of the cylindrical body, and (c) is an enlarged cross-sectional view of a part of the cylindrical body. [Figure 8] (a) to (d) are explanatory diagrams showing the insert molding process for a cylindrical body according to an embodiment of the present invention. [Figure 9] The following diagrams illustrate an experimental configuration according to an embodiment of the present invention: (a) is a plan view of the sample, (b) is a cross-sectional view of the joint, and (c) is an enlarged cross-sectional view showing a part of the joint. [Modes for carrying out the invention]

[0012] The embodiments for carrying out the present invention will be described below with reference to the attached drawings. Note that the configurations shown below are merely examples, and for example, those skilled in the art can modify the details as appropriate without departing from the spirit of the present invention. Furthermore, the numerical values ​​mentioned in this embodiment are for reference only and do not limit the present invention.

[0013] <Embodiment 1> Figures 1(a) and 1(b) show a cylindrical continuous carbon fiber reinforced resin molded body (cylindrical body) constituting a lens barrel component in this embodiment, in plan view and cross-sectional view, respectively. The cylindrical body 1 in Figures 1(a) and 1(b) is a cylindrical body that forms a lens barrel component in optical equipment such as interchangeable lenses for cameras, for example, a lens hood, a focus ring, or the body of the lens barrel, and is constructed as a cylindrical continuous carbon fiber reinforced resin molded body. Here, the lens hood is a light-shielding component that blocks unwanted light other than the photographic light from entering the photographic optical system, and is configured to be detachably attached to the front of an optical equipment (imaging device) such as a camera. Furthermore, lens barrel components such as the outer cylinder, inner cylinder, and focus ring of the lens barrel can be considered as lens barrel components that constitute the body of the lens barrel that holds or adjusts optical elements such as lenses and mirrors.

[0014] The cylindrical body 1 in Figure 1 is formed by solidifying a fiber layer (sometimes referred to as the first fiber layer) consisting of carbon fiber braid layers 3 and 5 with resin. For example, the resin for solidification is pre-included in the fiber layer in the form of impregnation or coating. In other words, an intermediate body 2 is prepared in which a resin for solidification is pre-included in a plurality of continuous carbon fibers in the form of impregnation or coating. This intermediate body 2 is interwoven into a cylindrical shape to form a fiber layer (first fiber layer) such as braid layer 3 and braid layer 5. At this time, it is preferable that the plurality of intermediate bodies 2 are assembled at an inclination with respect to the axial direction of the cylindrical body. Alternatively, a second fiber layer (unidirectional prepreg sheet layer) may be formed together with the fiber layer (first fiber layer). That is, the cylindrical body 1 may be formed by solidifying the first fiber layer and the second fiber layer with resin. In that case, for example, it is preferable that the resin for solidification is pre-included in the unidirectional prepreg sheet layer 4, which serves as the second fiber layer, in the form of impregnation or coating.

[0015] In the cylindrical bodies 1 shown in FIGS. 1(a) and 1(b), a unidirectional prepreg sheet layer 4 (second fiber layer) is positioned between the braided layers 3 and 5 (first fiber layers) respectively braided from the intermediate bodies 2 of carbon fibers. In this case, for example, on a mandrel (FIG. 2), first, the braided layer 5 (first fiber layer) is braided by a braiding device, and then, with the unidirectional prepreg sheet layer 4 (second fiber layer) positioned therebetween, the outer braided layer 3 (first fiber layer) is braided by the braiding device.

[0016] The braided layers 3 and 5 (first fiber layers) of carbon fibers are braided from the intermediate bodies 2 made of filamentous or tape-like carbon fibers by a braiding device (FIG. 2) into, for example, a cylindrical body having an endless form in the circumferential direction. In that case, the intermediate bodies 2 constituting the braided layers 3 and 5 (first fiber layers) are assembled in a direction inclined in the axial direction of the cylindrical body. In this embodiment, at least one layer of this carbon fiber braided layer may be braided. For example, the inner circumferential braided layer 5 may be omitted, and a structure may be adopted in which the outer circumferential braided layer 3 is braided with the unidirectional prepreg sheet layer 4 (second fiber layer) sandwiched on the mandrel.

[0017] As shown in FIG. 1(b), in order to position the unidirectional prepreg sheet layer 4 (second fiber layer) between the braided layers 3 and 5 (first fiber layers) of carbon fibers, for example, first, on the inner circumferential braided layer 5, a small amount of the end portion of the outer circumferential braided layer 3 is braided. Then, the tip of the carbon fiber material of the unidirectional prepreg sheet layer 4 is inserted there. Also, if possible, after braiding the outer circumferential braided layer 3 on the inner circumferential braided layer 5 for a required length, a method may be adopted in which the carbon fiber material of the unidirectional prepreg sheet layer 4 is inserted from one end portion between the braided layers 3 and 5 (first fiber layers) of carbon fibers.

[0018] As described above, in this embodiment, when the cylindrical body 1 constituting the lens barrel component is made of carbon fiber reinforced resin, its layer structure includes at least one braided layer of carbon fibers (first fiber layer: 5, 3) that is braided in an endless manner in the circumferential direction. That is, the braided layer (first fiber layer: 5, 3) in this embodiment is in an endless manner in the circumferential direction, and there are no seams in the carbon fiber layer that inevitably occur in conventional structures where only a unidirectional prepreg sheet is wound onto a mandrel. Therefore, there is no strength degradation due to seams in the carbon fiber sheet as in conventional structures, and it is possible to construct a lens barrel component with excellent strength such as rigidity and impact resistance. Furthermore, since the braided layer (first fiber layer: 5, 3) can be braided in an endless manner in the circumferential direction, and no unevenness in the circumferential structure of the cylindrical body 1 occurs due to seams. For example, in the case of a cylindrical lens barrel component, it is possible to obtain a lens barrel component with excellent roundness.

[0019] In this embodiment, when the cylindrical body 1 constituting the lens barrel component is manufactured from carbon fiber reinforced resin, it is sufficient to use at least one layer of braided carbon fibers (first fiber layer) that are braided to form an endless shape in the circumferential direction. For example, in the examples of Figures 1(a) and (b), a unidirectional prepreg sheet layer 4 is placed between the braided layers 3 and 5, but the unidirectional prepreg sheet layer 4 may be omitted, and the cylindrical body 1 may be constructed with two braided layers 3 and 5. The braided layer 5 on the inner circumference in Figures 1(a) and (b) may be changed to a unidirectional prepreg layer. Alternatively, the unidirectional prepreg sheet layer 4 may be changed to a braided layer, in which case the cylindrical body 1 will be formed by three braided layers. Furthermore, one to several braided layers may be braided on the outer circumference of the braided layer 3.

[0020] The carbon fibers used as the material for the unidirectional prepreg sheet layer 4 may be filamentous carbon fiber bundles or, for example, a single rectangular carbon fiber sheet, containing carbon fibers oriented in one direction, for example, substantially along the axial or circumferential direction of the cylindrical body 1. Preferably, carbon fibers oriented along the axial direction of the cylindrical body 1 are easier to handle during manufacturing and may provide good strength to the lens barrel component used in a near-horizontal position. Alternatively, the unidirectional prepreg sheet layer 4 may be constructed by arranging several carbon fiber tapes separated along the axial direction of the cylindrical body 1 along multiple axes. In this case, it is preferable that there are no gaps between the arranged tapes, but gaps are acceptable.

[0021] As described above, in this embodiment, in the cylindrical body 1 constituting the lens barrel component, in addition to the carbon fiber braid layers 3 and 5, a unidirectional prepreg sheet layer 4 containing, for example, fibers oriented in the axial direction of the cylindrical shape is arranged. This makes it possible to ensure strength and rigidity in the longitudinal direction in, for example, a long (large) and heavy imaging optical system with a long focal length.

[0022] To solidify the cylindrical body 1 into the finished shape of the lens barrel component, after the braiding process is completed, the mandrel, or the layered structure of the cylindrical body 1, is re-mounted in another mold corresponding to the finished shape, and then resin impregnation and solidification is performed. For this resin solidification, methods such as heating with a heater or pressurization with an autoclave are used. During the sintering of the resin for solidification, the shape may be controlled by applying pressure from another mold on the outside of the mandrel as needed.

[0023] For resin impregnation and solidification, for example, a carbon fiber material in which a solidification resin has been pre-impregnated into the thread-like or tape-like intermediate 2 of the braided layers 3 and 5, or into the unidirectional prepreg sheet layer 4, is used. Alternatively, carbon fiber material that has not been prepreg with resin may be used in these layers, and the resin for impregnation and solidification may be applied later by coating or spraying.

[0024] After solidification, the dissolved and solidified resin is distributed between the carbon fiber braid layers 3 and 5 (first fiber layers) and the unidirectional prepreg sheet layer 4 (second fiber layer), fixing these layers together.

[0025] As the resin for solidification, for example, a thermoplastic resin such as polycarbonate can be used by pre-impregnating the continuous carbon fibers of the braided layers 3 and 5 (first fiber layers) and the unidirectional prepreg sheet layer 4 (second fiber layer). However, a thermoplastic resin is not necessarily required as the resin for solidification, and those skilled in the art may change the resin to a thermosetting resin or a photocurable resin as needed.

[0026] As a method for manufacturing the resin-impregnated carbon fiber material, for example, in the case of the unidirectional prepreg sheet layer 4 (second fiber layer), a continuous carbon fiber sheet material having unidirectional orientation and a thermoplastic resin film are treated with a heated roll or the like to integrate them and obtain a prepreg sheet. Alternatively, this prepreg sheet can be cut into thread or tape shapes to produce an intermediate 2 for the braided layers 3 and 5 (first fiber layers). Furthermore, as the resin-impregnated carbon fiber material for the intermediate 2 for the braided layers 3 and 5 (first fiber layers), a blended yarn made by blending continuous carbon fibers and thermoplastic resin yarn may be used. Alternatively, the continuous carbon fibers may be impregnated by electrostatically attaching thermoplastic resin powder to them.

[0027] Impregnating the intermediate 2 with thermoplastic resin so that no fine voids remain inside is not easy, and it is also necessary to give the intermediate 2 flexibility when forming the braid layers 3 and 5. Therefore, a semi-impregnated state of thermoplastic resin is preferable for the continuous carbon fibers. A preferred semi-impregnated state is one in which the resin density is approximately 40% to 70% compared to a state in which the intermediate 2 is 100% impregnated without any voids as theoretically expected at the set VF (fiber volume content) value.

[0028] Furthermore, in the thermoplastic resin impregnation process, a sizing agent may be used to enhance the affinity between the carbon fibers and the thermoplastic resin. For example, by attaching an epoxy emulsion-based sizing agent to the carbon fibers, the interfacial adhesion between the carbon fibers and the thermoplastic resin can be improved. In this case, it is desirable that the carbon fiber bundles be opened to obtain good resin impregnation.

[0029] The cylindrical body 1 shown in Figures 1(a) and (b) can be thought of as having, for example, a cylindrical shape with a perfectly circular cross-section, but its cylindrical shape is arbitrary. Any shape can be adopted, such as a cone shape, a cone or horn shape where the inclination angle of the cone changes in the axial direction, or a constricted shape. Furthermore, the shape of the cylindrical body 1 is not limited to a cone shape; it may also have a pyramidal shape, etc. In addition, in the case of a cone shape or constricted shape where the inclination angle changes in the axial direction, an R shape can be added to the point where the inclination angle changes.

[0030] In this embodiment, polycarbonate is used as the thermoplastic resin pre-impregnated into the carbon fibers. The impact resistance of the polycarbonate itself improves the toughness of the cylindrical body 1, making it possible to obtain a high-strength lens barrel component. In applications such as this embodiment, the viscosity-average molecular weight of the polycarbonate used as the thermoplastic resin for solidification is preferably in the range of approximately 18,000 to 25,000. If the viscosity-average molecular weight of the polycarbonate is 18,000 or less, the toughness decreases, and if it is 25,000 or more, the melt viscosity tends to increase, which may reduce the impregnation performance in the solidification (sintering) process.

[0031] Figure 2 shows the configuration of a braiding apparatus 6 that can be used in the process of braiding (making) the carbon fiber braided layers 3 and 5 of Figure 1. In Figure 2, the braiding apparatus 6 has an annular frame 7 with a through hole 9. The mandrel 8 is positioned by means not shown, with the mandrel 8 inserted near the axis of the through hole 9 of the annular frame 7. The annular frame 7 is equipped with carriers 10 and 11 on which the braided yarns 12 and 13 that constitute the intermediate body 2 of the braided layers 3 and 5 are wound. The carriers 10 and 11 are driven by means not shown to displace along an eight-shaped track 14 formed around the pipe body 15, causing the annular frame 7 to circumvent each other in opposite directions. As a result, the braided layer 3 or 5 of the cylindrical body 1 of Figure 1 is made from the braided yarns 12 and 13, for example by the braiding method. In Figure 2, 16 is a simplified illustration of a tubularly braided fiber layer.

[0032] Each carrier 10 and 11 has a bobbin (details not shown) incorporated into it, and the braided threads 12 and 13 of the intermediate body 2 are wound onto these bobbins. Each carrier 10 and 11 also has a mechanism (details not shown) that generates tension using spring force or the like for winding the braided threads 12 and 13 onto the mandrel 8. The movement directions of carrier 10 and carrier 11 are opposite to each other. That is, carriers 10 and 11 move in opposite directions along the figure-eight trajectory 14 formed on the annular frame 7. This movement of carriers 10 and 11 forms braided layers (3 to 5: Figure 1) on the mandrel 8.

[0033] In Figure 2, for simplification, only two sets of braided yarns 12 and 13 are shown. However, on the annular frame 7, the braided yarns corresponding to each set are supplied from adjacent carriers 10 and 11 to the braiding position on the mandrel 8. Also, in Figure 2, the number of carriers 10 and 11 on the annular frame 7 is assumed to be 36, but the number of carriers 10 and 11 can be arranged according to the required number of braided yarns, depending on the size and shape of the intended lens barrel component. Alternatively, the annular frame 7 may be configured by arranging multiple pipe bodies 15 in a ring and supplying braided yarns from these pipe bodies 15 toward the mandrel 8 to assemble a tubular fiber layer 16.

[0034] The tubular fiber layer 16, which is wrapped around the mandrel 8, is heated using a heating means (not shown, such as a heater), and pressurization using an autoclave or the like is applied as needed to carry out the sintering and solidification process of the impregnating resin. At this time, molding pressure can be applied by pressing the outer mold or by the tension of wrapping metal tape or the like. This sintering process increases the degree of impregnation of the carbon fibers and thermoplastic resin in the intermediate body 2, and then, after cooling, decore removal from the mandrel 8, and end cutting processes, a tubular body 1 as a lens barrel component can be manufactured. In this embodiment, since a thermoplastic resin (polycarbonate) is used as the impregnating resin, there is an advantage in that the sintering process time is shorter and productivity can be improved compared to, for example, a thermosetting resin. In order to smoothly decore the tubular body 1 from the mandrel 8, a release agent can be applied to the mandrel in advance, or a surface treatment such as hard Cr plating or polytetrafluoroethylene film deposition can be applied.

[0035] Figures 3(a) and 3(b) show a structure in which a ring-shaped resin part is provided as a covering part 17 at the end 18 of the cylindrical body 1, which is a lens barrel component configured as described above. The covering part 17 constitutes a mechanism or part thereof for, for example, fixing the cylindrical body 1 to other lens barrel components, or, if the cylindrical body 1 is a lens hood, for attaching and detaching it from other lens barrel components.

[0036] The structure shown in Figures 3(a) and 3(b) is covered with a resin component formed as a covering portion 17 on at least one end 18 of the cylindrical body 1. The covering portion 17 can be formed, for example, by insert injection molding of a thermoplastic resin. For example, the cylindrical body 1 manufactured as described above is inserted into an injection molding die, and the covering portion 17 is formed and integrated with the cylindrical body 1 by injection molding of a thermoplastic resin containing fibers. This insert molding process is shown in detail in Figure 6, which will be described later.

[0037] To obtain sufficient strength for use as a fixing or detaching part of the lens barrel components, the covering portion 17 is preferably made of a thermoplastic resin containing fibers. For example, polycarbonate can be used as the thermoplastic resin constituting the covering portion 17. In the case of polycarbonate, its own good impact resistance makes it possible to obtain lens barrel components with improved toughness of the mounting portion, etc., formed by the covering portion 17.

[0038] By forming the covering portion 17 on the end portion 18 of the cylindrical body 1, ring portions and other parts for use as fastening or detaching parts, which cannot be created in the braiding or solidification process of the cylindrical body 1, can be provided on the lens barrel component. Furthermore, by using a thermoplastic resin containing fibers, the strength of the attachment portion etc. formed by the covering portion 17 can be maintained. The fibers referred to here are not particularly limited as long as they are fibrous, but generally they are short fibrous glass fibers or carbon fibers or both with a length of 1 mm or less. In this case, the fiber content is not particularly limited, but a range of about 20% to 40% is preferred.

[0039] The covering portion 17 can be molded to any shape and size depending on the performance, specifications, and dimensions required for use as a fixing or detaching part of the lens barrel components. In the structures shown in Figures 3(a) and 3(b), the covering portion 17 is molded to cover the circumference of one end 18 of the cylindrical body 1, and a flange portion 17a protruding in the inward direction is formed on the inside of the end 18. When the cylindrical body 1 is the body of a lens barrel, the flange portion 17a is used as a support for optical elements or a focus ring. Furthermore, for example, when the cylindrical body 1 is a lens hood that can be attached to and detached from the main body of a photographic optical system, the resin component configured as the covering portion 17 can be used as part of the mechanism for attaching and detaching the lens hood.

[0040] Figures 4(a), (b), and (c) show different structures for providing a ring-shaped resin component as a covering portion 17 to the end 18 of the cylindrical body 1, which serves as a lens barrel component, as described above. Figures 4(a) and (b) are plan and cross-sectional views in the same style as Figures 3(a) and (b), and Figure 4(c) is an enlarged cross-sectional view of the circled area in Figure 3(b).

[0041] In Figure 4, 20 is the circumscribed circle formed by the thickest part of the cylindrical body 1, and the diameter of this circumferential surface is φ. The difference between the configuration in Figure 4 and Figure 3 is that, as shown in particular in detail in Figure 4(c), the circumferential surface of the covering part 17 as a resin component is located inside the circumferential surface of the cylindrical body 1 (circumscribed circle 20), and this part is the exposed portion 21 of the end 18 of the cylindrical body 1. The amount of exposure 22 of the exposed portion 21, that is, the distance between the circumferential surface of the covering part 17 and the circumferential surface of the cylindrical body 1 (circumscribed circle 20), is set to be a greater distance than the thickness distribution that occurs during the braiding of the braided layers 3 and 5 described below, at least 0.1 mm or more.

[0042] This structure is designed to ensure good insert molding of the covering portion 17. For example, during the braiding of the braid layers 3 and 5, irregularities occur in the overlapping portions of the intermediate body 2, resulting in a distribution of thick and thin portions in the cylindrical body 1. For example, in Figure 2, during the process of winding the fiber layer 16 onto the mandrel 8, gaps tend to form more easily between the braided threads (intermediate body 2) in the braid layer 3 of the mandrel 8 than in the braid layer 5 on the inner circumference of the mandrel 8. This variation in the thickness of the cylindrical body 1 occurs by about 0.1 mm in the height of the circumferential surface of the cylindrical body 1 in the case of standard carbon fiber material.

[0043] Due to the characteristics of the braided layers 3 and 5 described above, a portion of the outer surface of the cylindrical body 1 is formed that is thinner than the rest. When the cylindrical body 1 is set in the injection mold for insert molding of the covering portion 17, a gap is created between the cylindrical body 1 and the mold in the thin portion of its outer surface. For example, as shown in Figure 3, in a structure where there is no exposed portion 21 at the end 18 of the cylindrical body 1, the cavity for the covering portion 17 and the gap between the mold and the thin portion of the cylindrical body 1's outer surface are in communication. Therefore, when the resin for the covering portion 17 is injected into the cavity, the thermoplastic resin enters the gap between the outer surface of the cylindrical body 1 and the mold, potentially causing burrs to form on the outer surface near the end 18 of the cylindrical body 1. In particular, if burrs form on the outer surface of the cylindrical body 1 used as a lens barrel component as described above, it will degrade the appearance quality of the lens barrel component.

[0044] In contrast, as shown in Figure 4, the shape of the covering portion 17 is determined so that an exposed portion 21 is formed at the end 18 of the cylindrical body 1 with an exposure amount 22 greater than or equal to the thickness distribution (0.1 mm), and an injection mold is fabricated for insert molding the covering portion 17. As a result, even if there is variation in the thickness distribution of the circumferential surface of the end 18 of the cylindrical body 1 due to the braiding of the braid layers 3 and 5, the exposure amount 22 of the exposed portion 21 is set to be larger than that. Therefore, the mold reliably seals the edge portion 19 (Figure 4(c)) of the circumferential surface of the end 18 of the cylindrical body 1 so that resin does not enter the circumferential surface. As a result, compared to the structure without the exposed portion 21 in Figure 3, burrs generated by insert molding of the covering portion 17 on the circumferential surface of the end 18 of the cylindrical body 1 can be suppressed well. Therefore, it is possible to manufacture lens barrel parts with good dimensional accuracy and a beautiful appearance.

[0045] <Embodiment 2> Hereinafter, modifications of Embodiment 1 described above will be explained with reference to Figures 7(a), (b), and (c).Hereinafter, the same reference numerals will be used for components that are the same as or equivalent to those described above, and detailed explanations will be omitted unless particularly necessary.Figures 7(a) and (b) show the side view and cross-section of the cylindrical body 1 with the completed covering portion 17, respectively, and Figure 7(c) shows a detailed cross-section of the portion indicated by the circle in Figure 7(b).

[0046] In the configuration shown in Figure 7, the covering portion 17 is formed, for example, by insert injection molding of a thermoplastic resin. For example, the cylindrical body 1 is inserted into an injection molding die, and the covering portion 17 is formed and integrated with the cylindrical body 1 by injection molding of a thermoplastic resin containing fibers. This insert molding process is shown in detail in Figure 8, which will be described later.

[0047] This embodiment is characterized by the formation of a resin layer 40 on the surface of the cylindrical body 1. In Figure 7(c), 40 represents the resin layer of this embodiment, and 41 in the figure represents an extremely thin resin layer. This extremely thin resin layer 41 originates from the intermediate 2 that constitutes the braided layers 3 and 5. That is, the resin pre-impregnated in the intermediate 2 forms an extremely thin resin layer 41 of 5 to 15 μm on the surface of the cylindrical body 1 through a solidification process. This extremely thin resin layer 41 plays a role in preventing strength degradation caused by the carbon fiber material being exposed on the outer surface.

[0048] However, this ultra-thin resin layer 41 is relatively fragile, and there are concerns that it may affect the bonding strength between the cylindrical body 1 and the covering portion 17. For example, a deterioration in bonding strength may occur due to the ultra-thin resin layer 41 being fragmented because carbon fibers penetrate it in areas where it is not completely covered. In this regard, by providing a resin layer 40, the fragmentation of the ultra-thin resin layer 41 can be filled, and a deterioration in bonding strength can be prevented.

[0049] Furthermore, if, for example, the adhesion between the ultra-thin resin layer 41 and the carbon fibers is insufficient, a deterioration in bonding strength may occur. In this regard, by providing the resin layer 40, its heat-insulating effect generates heat storage from the resin during injection molding when forming the coating portion 17, increasing the activation energy between the ultra-thin resin layer 41 and the carbon fibers. Then, by utilizing the pressure when forming the coating portion 17, the ultra-thin resin layer 41 and the carbon fibers can be firmly bonded.

[0050] In order to utilize the heat insulation effect, the thickness of the resin layer 40 must be between 50 μm and 200 μm. If the thickness of the resin layer 40 is less than 50 μm, the heat insulation effect cannot be achieved, and heat from the resin escapes to the mold side through the cylindrical body 1, preventing the desired temperature rise between the ultrathin resin layer 41 and the carbon fibers. Furthermore, if the thickness is 200 μm or more, the increased thickness of the resin layer 40, due to its own heat capacity, prevents the desired temperature rise between the ultrathin resin layer 41 and the carbon fibers. Moreover, a thickness of 200 μm or more is unsuitable from the perspective of weight reduction, which is the original objective.

[0051] Considering the above, a thermoplastic resin such as polycarbonate is used as the resin for the resin layer 40. Furthermore, considering the insert molding process of the covering portion 17, it is preferable that the resin layer 40 and the covering portion 17 are made of resins with high affinity for each other, and in particular, it is preferable that they be the same resin. In addition, it is desirable that the resin layer 40 and the resin pre-impregnated in the intermediate 2 constituting the braided layers 3 and 5 have high affinity for each other, and preferably be the same resin. By combining materials in this way, the bonding strength between the resin layer 40, the covering portion 17, and the ultrathin resin layer 41 can be increased.

[0052] In this embodiment, the resin layer 40 is made of polycarbonate. For applications such as those in this embodiment, the viscosity-average molecular weight of the polycarbonate is preferably in the range of approximately 18,000 to 25,000. For example, if the viscosity-average molecular weight of the polycarbonate is 18,000 or less, the toughness decreases, and if it is 25,000 or more, the melt viscosity tends to increase, which may lead to a deterioration in the bonding strength between the resin layer 40 and the ultrathin resin layer 41 during the impregnation process.

[0053] One method for forming the resin layer 40 is to wrap a film-like thermoplastic resin, which will become the resin layer 40, around a fiber layer 16 in which the intermediate 2 has been pre-assembled into a tubular shape. Then, by heating (and pressurizing as necessary) the intermediate 2 and the wrapped thermoplastic resin, an ultra-thin resin layer 41 of 5 to 15 μm and the resin layer 40 on the surface of the tubular body 1 can be formed. As for the method of wrapping this film-like thermoplastic resin, for example, after manufacturing the fiber layer 16 in which the intermediate 2 has been assembled into a tubular shape, a winding method can be used in which a filament of thermoplastic resin processed into a tape shape from the film is filament-wound. Alternatively, as another method, for example, after manufacturing the fiber layer 16 in which the intermediate 2 has been assembled into a tubular shape, a tape-shaped film of thermoplastic resin may be twisted into a cord and then wound around the fiber layer 16 in which the intermediate 2 has been assembled into a tubular shape.

[0054] Alternatively, a cylindrical body 1 may be manufactured with an ultrathin resin layer 41 of 5 to 15 μm thickness formed on its surface. Then, a filament of thermoplastic resin, processed from a film into a tape shape, is wound onto the ultrathin resin layer 41 using filament winding. After winding, the thermoplastic resin is heated (and pressurized as necessary) to form a resin layer 40 on the 5 to 15 μm ultrathin resin layer 41 on the surface of the cylindrical body 1.

[0055] Alternatively, one could manufacture a cylindrical body 1 with an ultrathin resin layer 41 of 5 to 15 μm thickness formed on its surface, and then wind a tape-shaped film of thermoplastic resin onto the ultrathin resin layer 41. After winding, the thermoplastic resin is heated (and pressurized as necessary) to form a resin layer 40 on the 5 to 15 μm ultrathin resin layer 41 on the surface of the cylindrical body 1.

[0056] Subsequently, the cylindrical body 1 with the resin layer 40 formed on it is inserted into a mold, and a covering portion 17 is formed on the resin layer 40 by injection molding to integrate them. Alternatively, a method may be used in which a film to be formed as the resin layer 40 is wound to a thickness greater than the specified thickness, and then the resin layer 40 is trimmed to the specified thickness.

[0057] If the surface of the cylindrical body 1 has irregularities due to the assembly of the intermediate body 2, the appearance quality may be reduced when applying a coating to the lens barrel component for purposes such as heat shielding. However, as in this embodiment, by winding a film that will become the resin layer 40 with a thickness of 50 μm or more and 200 μm or less to form the resin layer 40, or by further shaving the resin layer 40 to a specified thickness, the resin layer 40 other than the coated portion 17 to which the coating is applied can be made smooth. This significantly improves the appearance quality of the coating. Alternatively, a method may be adopted in which the resin layer 40 is formed to a specified thickness only in the area where the coated portion 17 is formed, and the other resin layers 40 are shaved to a thickness of less than the specified thickness. This allows for maintaining the thickness of the resin layer 40 due to bonding strength, while making the other appearance quality parts smooth by shaving, and also contributes to weight reduction.

[0058] <Example 1> Figures 5(a), (b), and (c) show the configuration of the covering portion 17, which has been further modified from Figures 4(a), (b), and (c). Figures 6(a) to (d) show the insert molding process of the covering portion 17 onto the cylindrical body 1. Below, the configuration of the cylindrical body 1 and the details of the manufacturing process will be explained in detail with reference to Figures 5 and 6.

[0059] In Figure 5(a), 23 indicates the braiding angle of the intermediate body 2 that constitutes the braided layer (3 or 5). That is, the intermediate body 2 that constitutes the braided layers 3 and 5 is braided in a direction inclined by the braiding angle 23 in the axial direction of the cylindrical body. As shown in Figure 5(b) or (c), the laminated structure of the cylindrical body 1 is a three-layer structure consisting of the braided layer 3, the unidirectional prepreg sheet layer 4, and the braided layer 5 from the inner circumference side, as described above.

[0060] For the intermediate material 2 used to braid the braided layers (3 or 5), for example, a prepreg sheet is used, which is made by electrostatically attaching thermoplastic resin powder to an open-fiber carbon fiber sheet and then heating it, and then cutting the prepreg sheet into a tape shape. For the unidirectional prepreg sheet layer 4, for example, the sheet material is wrapped around the braided layer 5 in advance before braiding the third braided layer 3, and then positioned between the layers while braiding the braided layer 3.

[0061] Furthermore, the VF of the intermediate 2 of the braided layer (3 or 5) and the unidirectional prepreg sheet are both set to 50%, for example, and the impregnation resin for both is polycarbonate with a viscosity-average molecular weight of 20,000. The theoretical thickness of intermediate 2 when 100% impregnated is 0.115 mm, and the density of the thermoplastic resin in the partially impregnated state of intermediate 2 when braided layers 3 and 5 are formed is set to 50% to 60%. The cylindrical body 1, which is composed of a three-layer structure consisting of a braided layer 3, a unidirectional prepreg sheet layer 4, and a braided layer 5 made of such materials and manufactured by the process described below, is assumed to have a theoretical thickness of approximately 0.575 mm (Table 1 below).

[0062] The braiding angle 23 of the intermediate body 2 and the orientation direction of the carbon fibers in the unidirectional prepreg sheet are determined considering the strength and rigidity of the finished product when used as a lens barrel component. For example, it is preferable to use different braiding angles (23), such as 30° for the braiding angle of the inner braiding layer 3 and 60° for the braiding angle of the outer braiding layer 5. In addition, the orientation direction of the carbon fibers in the unidirectional prepreg sheet is made to approximately coincide with the direction along the cylindrical axis of the cylindrical body 1.

[0063] The tubular fiber layer 16 (Figure 2), which is formed by braiding (first step) on the mandrel 8 using the braiding apparatus 6 shown in Figure 2, is heated using a heating means (such as an autoclave, not shown) to solidify the thermoplastic resin that is impregnated (second step). Although it varies depending on the specifications of the lens barrel components that make up the tubular body 1, for example, a cylindrical mandrel 8 with a diameter of Φ69 mm is used. In addition, the mandrel 8 is subjected to a surface treatment to facilitate demolding, such as polytetrafluoroethylene plating.

[0064] In the solidification process, molding pressure is applied from the outer periphery of the tubular fiber layer 16. For example, by applying pressure using the tension of wrapping a metal tape, the impregnation, bonding, and solidification of the carbon fibers and thermoplastic resin within the intermediate 2 can be promoted. In addition, in the solidification process, it is also conceivable to use inner and outer molds with different shapes from the mandrel 8 to form the final shape of the tubular body 1 (for example, a truncated pyramidal shape).

[0065] After the mandrel 8 and cylindrical body 1 are cooled, the cylindrical body 1 is removed from the mandrel 8, and the end 18 is cut and shaped as appropriate to complete the cylindrical body 1.

[0066] Table 1 shows the characteristics of the cylindrical body manufactured under the above conditions and the comparative example. Table 1 shows the results of compression tests performed in the cylindrical axis direction on the cylindrical body (left side of Table 1: Example) and the cylindrical body (right side of Table 1: Comparative Example) manufactured under the above conditions.

[0067] [Table 1]

[0068] The cylindrical body of the embodiment (Table 1, left side) consists of the braided layers 3 and 5 and the unidirectional prepreg sheet layer 4 (Figures 5(b) and (c)). The cylindrical body of the comparative example (Table 1, right side) uses a unidirectional prepreg sheet impregnated with hydrogenated bisphenol A epoxy resin, and is repeatedly laminated in six layers, changing the fiber orientation direction in the cylindrical axis direction and the circumferential direction of the cylindrical body, and then solidified. Unlike the embodiment described above, the cylindrical body of this comparative example (Table 1, right side) does not use a cylindrical braided layer, but is formed by winding a unidirectional prepreg sheet. The theoretical thickness of the cylindrical body of the comparative example (Table 1, right side) is 0.84 mm. In contrast, the theoretical thickness of the cylindrical body of this embodiment (Table 1, left side) is 0.575 mm, making it thinner and lighter. Moreover, despite being thinner than the cylindrical body of the comparative example (Table 1, right side), the cylindrical body of this embodiment (Table 1, left side) achieves a compressive fracture strength equal to or greater than that of the comparative example.

[0069] In the following, with reference to Figure 6, a configuration in which a resin component is insert-molded as a covering portion 17 into the end 18 of the cylindrical body 1 after the solidification process, and an example of the insert molding process will be described in detail. Here, as explained in Figure 5, a covering portion 17 is formed having an exposed portion 21 with an exposure amount 22 of 0.1 mm from the circumscribed circle 20, which is the thickest part. In this example, as shown in Figures 5(b) and (c), the edge portion 19 of the end 18 of the cylindrical body 1 is chamfered to a thickness of 0.05 mm or less. This chamfer of the edge portion 19 can be formed, for example, by cutting before insert molding of the covering portion 17.

[0070] Figures 6(a) to (d) show, in order of process, cross-sections of a mold for insert molding a resin part as a covering portion 17 onto the end 18 of the cylindrical body 1 after the solidification process. In Figures 6(a) to (d), the insert molding mold 24 consists of a fixed mold 25 and a movable mold 26, and is mounted on an injection molding machine 30.

[0071] As shown in Figures 6(a) and (b), the fixed mold 25 and the movable mold 26 have cavities 28 formed therein to accommodate the solidified cylindrical body 1. As shown in Figure 6(a), Figure 6(b) shows the state in which the solidified cylindrical body 1 is housed in this cavity 28 and the mold is clamped. In this state, a mold shape 27 for molding the covering portion 17 is provided at the position of the fixed mold 25 corresponding to the end portion 18 of the cylindrical body 1, with the structure shown in Figures 5(b) and (c). In the fixed mold 25, this mold shape 27 is shaped to seal the edge of the cylindrical body 1 so that an exposed portion 21 is formed. This mold shape 27 effectively prevents the resin from overflowing from the cavity 28 on the inner circumference side of the end portion 18 of the cylindrical body 1 toward the outer circumference of the cylindrical body 1 and becoming a burr when the molding resin 32 is poured as shown in Figure 6(c).

[0072] In the insert molding process for the covering portion 17, first, as shown in Figure 6(a), the cylindrical body 1 is set in the cavity 28 of the movable mold 26 of the insert molding die 24, and then, as shown in Figure 6(b), the fixed mold 25 and the movable mold 26 of the insert molding die 24 are clamped together.

[0073] Furthermore, as shown in Figure 6(c), the molten molding resin 32 is injected and filled into the insert mold 24 via the spool, runner, and gate (31: Figure 6(a)) of the injection molding machine 30. In this embodiment, the mold shape 27 allows the fixed mold 25 to seal the end 18 so that an exposed portion 21 is formed at the end 18 of the cylindrical body 1, thereby preventing the molding resin 32 from leaking out of the cavity 28 toward the outer circumference of the cylindrical body 1 and becoming burrs. For the molding resin 32, for example, polycarbonate with 30% glass fiber is used. After that, by hardening the molding resin 32 through mold cooling, the cylindrical body 1 and the molding resin 32 are integrated, and the ring and flange-shaped covering portion 17 described above can be formed on the end 18 of the cylindrical body 1.

[0074] Subsequently, the injection molding machine 30 is driven to separate the fixed mold 25 and the movable mold 26 as shown in Figure 6(d), and the cylindrical body 1 and the portion of the runner 33 molded in the gate by the molded resin 32 are released using a release mechanism (not shown). In this way, a lens barrel component consisting of a cylindrical body 1 equipped with a resin part (covering part 17) can be manufactured, which has a high-quality appearance without burrs on the outer circumference.

[0075] <Example 2> Furthermore, as another embodiment, the structure and manufacturing process of the cylindrical body 1 described as Embodiment 2 will be explained in detail with reference to Figures 7 and 8.

[0076] As shown in Figure 7(b) or (c), the laminated structure of the cylindrical body 1 is a three-layer structure consisting of a braided layer 3, a unidirectional prepreg sheet layer 4, and a braided layer 5 from the inner circumference side, as described above. For the intermediate body 2 used to braid the braided layer (3 or 5), for example, a prepreg sheet is made by electrostatically attaching thermoplastic resin powder to an open-fiber carbon fiber sheet material and then heating it, and then cutting the prepreg sheet into a tape shape.

[0077] The sheet material for the unidirectional prepreg sheet layer 4 is, for example, wrapped around the braided layer 5 in advance before assembling the third braided layer 3, and then positioned between the layers while assembling the braided layer 3. The VF of the intermediate 2 of the braided layer (3 or 5) and the unidirectional prepreg sheet are both set to, for example, 50%, and the impregnation resin for both is polycarbonate with a viscosity-average molecular weight of 20,000.

[0078] The theoretical thickness of intermediate 2 when 100% impregnated is set to 0.115 mm, and the density of the thermoplastic resin in the partially impregnated state of intermediate 2 during the formation of braid layers 3 and 5 is set to 50% to 60%. The cylindrical body 1, which is constructed of three layers consisting of a braid layer 3, a unidirectional prepreg sheet layer 4, and a braid layer 5 made of such materials, is assumed to have a theoretical thickness of approximately 0.575 mm when manufactured through the process described below.

[0079] Using the braiding apparatus 6 shown in Figure 2, a tubular fiber layer 16 (Figure 2) is fabricated on a mandrel 8 by braiding (first step).

[0080] Next, a tape-shaped polycarbonate film is placed on one of the carriers 10 of the braiding device 6, and the polycarbonate film is wound around the tubular fiber layer 16 by performing filament winding.

[0081] The polycarbonate film used was pre-slit to a width of 5 mm. The polycarbonate film used had a viscosity-average molecular weight of 20,000.

[0082] Next, the tubular fiber layer 16, which is made up of polycarbonate film, is heated using a heating means to solidify the thermoplastic resin that is impregnated (second step). Although it varies depending on the specifications of the lens barrel components that make up the tubular body 1, for example, a cylindrical mandrel 8 with a diameter of Φ69 mm is used. In addition, the mandrel 8 is subjected to a surface treatment to facilitate mold release, such as polytetrafluoroethylene plating.

[0083] In the solidification process, molding pressure is applied from the outer periphery of the polycarbonate film wrapped around the tubular fiber layer 16. For example, by applying pressure using the tension of wrapping a metal tape, the impregnation, bonding, and solidification of the carbon fibers and thermoplastic resin within the intermediate 2 can be promoted, while integrating it with the polycarbonate film wrapped around the surface.

[0084] After the mandrel 8 and cylindrical body 1 are cooled, the cylindrical body 1 is removed from the mandrel 8, and the end 18 is cut and shaped as appropriate to complete the cylindrical body 1 with the resin layer 40 on the surface.

[0085] At that time, the resin layer 40 on the surface was made to a predetermined thickness by grinding. Below, with reference to Figure 8, the configuration in which a resin part is insert-molded as a covering part 17 into the resin layer 40 on the surface of the cylindrical body 1 that has undergone the solidification process, and an example of the insert molding process will be described in detail.

[0086] Here, the thickness 42 of the covering portion 17 shown in Figure 7 is set to 1.5 mm. Figures 8(a) to (d) show the cross-section of the mold for insert molding a resin part as a covering portion 17 into the resin layer 40 on the surface of the cylindrical body 1 after the solidification process, in order of the process. In Figures 8(a) to (d), the insert molding mold 24 consists of a fixed mold 25 and a movable mold 26, and is mounted on the injection molding machine 30.

[0087] As shown in Figures 8(a) and 8(b), the fixed mold 25 and the movable mold 26 have cavities 28 formed therein for accommodating the solidified cylindrical body 1. As shown in Figure 8(a), Figure 8(b) shows the state in which the solidified cylindrical body 1 is housed in the cavity 28 and the mold is clamped. In this state, a mold shape 27 for forming the covering portion 17 is provided.

[0088] In the insert molding process for the covering portion 17, first, as shown in Figure 8(a), the cylindrical body 1 with the resin layer 40 formed on it is set in the cavity 28 of the movable mold 26 of the insert molding die 24, and as shown in Figure 8(b), the fixed mold 25 and the movable mold 26 of the insert molding die 24 are clamped together. Furthermore, as shown in Figure 8(c), the molten molding resin 32 is injected and filled through the spool, runner, and gate (31: Figure 8(a)) of the insert molding die 24.

[0089] For the molding resin 32, for example, polycarbonate containing 30% glass fiber is used. Subsequently, by curing the molded resin 32 through processes such as mold cooling, the cylindrical body 1 and the molded resin 32 are integrated, and the above-described covering portion 17 can be molded onto the resin layer 40 of the cylindrical body 1.

[0090] Subsequently, the injection molding machine 30 is driven to separate the fixed mold 25 and the movable mold 26 as shown in Figure 8(d), and the cylindrical body 1 and the portion of the runner 33 molded in the gate by the molded resin 32 are released using a release mechanism (not shown). In this way, a lens barrel component consisting of a cylindrical body 1 equipped with a resin part (coating part 17) is obtained. After that, by painting the surface, a lens barrel component with a high-quality appearance can be manufactured.

[0091] Furthermore, regarding the predetermined thickness of the resin layer 40, since the actual strength relative to the thickness cannot be measured in the form of the cylindrical body 1, the joint strength was confirmed by conducting a tensile test. Figures 9(a) to (c) show the shape of the sample used in this tensile test. Figure 9(a) is a plan view of the sample, Figure 9(b) is a cross-section of the joint, and Figure 9(c) shows a detailed view of the cross-sectional structure of the circled part in Figure 9(b). In Figures 9(a) to (c), 50 is the experimental piece, 51 is the continuous carbon fiber reinforced resin molded body equipped with the resin layer 40 (Figures 9(b) and 9(c)), and 52 and 53 are the length and width of the continuous carbon fiber reinforced resin molded body 51. Also, 54 and 55 in the figures show the length and width of the covering part 17, and 56 and 57 in the figures show the length and width of the joint between the continuous carbon fiber reinforced resin molded body 51 and the covering part 17.

[0092] Here, lengths 52 and 54 were both set to 75 mm, and widths 53 and 55 were both set to 25 mm. The length 56 of the joint was set to 25 mm, and the width 57 was set to 25 mm. The laminated structure of the continuous carbon fiber reinforced resin molded body 51 consisted of three layers: a twill weave layer 58, a unidirectional prepreg sheet layer 59, and a twill weave layer 60. The VF of the twill weave layer (58 or 60) and the unidirectional prepreg sheet were both set to 50%, for example, and the impregnation resin for both was polycarbonate with a viscosity-average molecular weight of 20,000. The theoretical thickness of intermediate 2 when 100% impregnated is 0.115 mm, and the density of the thermoplastic resin in the semi-impregnated state of intermediate 2 when the twill weave layers 58 and 60 are formed is set to 50% to 60%.

[0093] The theoretical thickness of the continuous carbon fiber reinforced resin molded body 51, which is composed of three layers consisting of a twill weave layer 58, a unidirectional prepreg sheet layer 59, and a twill weave layer 60 made of such materials and manufactured by the process described below, is assumed to be approximately 0.575 mm.

[0094] A twill weave layer was prepared by weaving intermediate 2 in a twill weave. A unidirectional prepreg sheet layer 59 was placed between the twill weave layers 58 and 60, and a polycarbonate film was laminated on the side of the twill weave layer 58. The polycarbonate film used had a viscosity-average molecular weight of 20,000.

[0095] Next, the continuous carbon fiber reinforced resin molded body 51, on which polycarbonate films are laminated, is heated using a heating means to solidify the thermoplastic resin in the impregnated state (second step). In this solidification step, molding pressure is applied to the continuous carbon fiber reinforced resin molded body 51 using a flat mold and press device (not shown).

[0096] By applying pressure, the impregnation, bonding, and solidification of the carbon fibers and thermoplastic resin within the intermediate 2 can be promoted, while simultaneously integrating it with the polycarbonate film laminated on the surface. Subsequently, after the mold and the continuous carbon fiber reinforced resin molded body 51 are cooled, the mold is demolded and cut to complete the continuous carbon fiber reinforced resin molded body 51 with a surface resin layer 40 formed on it. At that time, grinding was performed to process the surface resin layer 40 to a predetermined thickness.

[0097] Subsequently, an experimental specimen 50, as shown in Figure 9, was created by insert molding a resin portion as a covering portion 17 into the resin layer 40 on the surface of the continuous carbon fiber reinforced resin molded body 51, which had undergone a solidification process. In this case, the thickness of the covering portion 17 shown in Figure 9 was 1.5 mm.

[0098] Table 2 below shows the bonding strength characteristics of the continuous carbon fiber reinforced resin molded body 51 manufactured under the above conditions, depending on the thickness of the resin layer 40. Table 2 shows the results of a tensile test performed on an experimental specimen 50 (example) manufactured under the above conditions. At this time, an electromechanical universal material testing machine manufactured by Instron was used, and 25 mm from both ends of the experimental specimen 50 was chucked in the testing machine and a tensile test was performed. In Table 2, the thickness of the resin layer 40 is the value obtained by subtracting the thickness dimension calculated from the theoretical thickness of the continuous carbon fiber reinforced resin molded body without the resin layer 40 from the actual thickness dimension of the continuous carbon fiber reinforced resin molded body 51 with the resin layer 40 present.

[0099] [Table 2]

[0100] As shown in Table 2, it can be seen that a tensile strength of 5 MPa or more can be obtained when the thickness of the resin layer 40 is between 50 μm and 200 μm. Furthermore, it can be seen that a structure in which a resin layer 40 with a thickness of 50 μm to 200 μm is provided on the surface of the cylindrical body is preferable. With such a structure, a lens barrel component with excellent bonding strength can be obtained. [Explanation of symbols]

[0101] 1...Cylindrical body, 2...Intermediate body, 3, 5...Braided layer, 4...Unidirectional prepreg sheet layer, 6...Braiding device, 7...Annular frame, 8...Mandrel, 9...Through hole, 10, 11...Carrier, 12, 13...Braided yarn, 14...Figure-eight track, 15...Pipe body, 17...Coating part, 18...End part, 19...Edge part, 20...Circumscribed circle, 21...Exposed part, 22...Amount of exposure, 23...Braided corner, 24...Insert molding die, 25...Fixed mold, 26...Movable mold, 28...Cavity, 40...Resin layer, 41...Ultra-thin resin layer.

Claims

1. An optical instrument including an optical element and a lens barrel for holding or adjusting the optical element, It is equipped with a cylindrical body which is a lens barrel component, The cylindrical body includes a cylindrical first carbon fiber layer, a cylindrical second carbon fiber layer located on the outer circumference side of the cylindrical body relative to the first carbon fiber layer, and a third carbon fiber layer provided between the first carbon fiber layer and the second carbon fiber layer. The first carbon fiber layer is a braided layer formed by intersecting a plurality of carbon fibers of the first carbon fiber layer and arranging them in a tubular shape, and is provided in an endless manner in the circumferential direction of the tubular body, wherein the plurality of carbon fibers of the first carbon fiber layer include carbon fibers oriented in a first direction inclined with respect to the axial direction of the tubular body and carbon fibers oriented in a second direction inclined with respect to the axial direction of the tubular body, and the first carbon fiber layer is impregnated with resin. The second carbon fiber layer is a braided layer in which a plurality of carbon fibers of the second carbon fiber layer are intersected and woven into a tubular shape, and which is provided in an endless manner in the circumferential direction of the tubular body, and the second carbon fiber layer is impregnated with resin. The first carbon fiber layer and the third carbon fiber layer are fixed together with resin, and the second carbon fiber layer and the third carbon fiber layer are fixed together with resin. An optical instrument characterized by the following features.

2. The plurality of carbon fibers in the second carbon fiber layer include carbon fibers oriented in a third direction inclined with respect to the axial direction of the cylindrical body, and carbon fibers oriented in a fourth direction inclined with respect to the axial direction of the cylindrical body. The optical instrument according to feature 1.

3. The first carbon fiber layer and the third carbon fiber layer are fixed together by the resin impregnated in the first carbon fiber layer, and the second carbon fiber layer and the third carbon fiber layer are fixed together by the resin impregnated in the second carbon fiber layer. The optical instrument according to claim 1 or 2.

4. The aforementioned third carbon fiber layer is a braided layer. The optical instrument according to any one of claims 1 to 3.

5. The carbon fibers in the third carbon fiber layer have a unidirectional orientation. The optical instrument according to any one of claims 1 to 3.

6. The cylindrical body includes a resin layer having a thickness of 5 μm to 15 μm, provided on the side opposite to the first carbon fiber layer relative to the second carbon fiber layer. The optical instrument according to any one of claims 1 to 5.

7. The resin impregnated in the first carbon fiber layer and the resin impregnated in the second carbon fiber layer are thermoplastic resins. The optical instrument according to any one of claims 1 to 6.

8. The thermoplastic resin is polycarbonate. The optical instrument according to feature 7.

9. The angle of assembly of the carbon fibers in the first carbon fiber layer with respect to the axial direction of the tubular body and the angle of assembly of the carbon fibers in the second carbon fiber layer with respect to the axial direction of the tubular body are different from each other. The optical instrument according to any one of claims 1 to 8.

10. The carbon fibers of the third carbon fiber layer intersect with the plurality of carbon fibers of the second carbon fiber layer. The optical apparatus according to claim 3 or 5, characterized by the features described herein.

11. The cylindrical body includes a ring-shaped resin covering attached to its end, The optical instrument according to any one of claims 1 to 10.

12. The resin of the coating is a thermoplastic resin containing fibers, and / or The resin of the covering part is polycarbonate. The optical instrument according to feature 11.

13. The circumferential surface of the cylindrical body is located 0.1 mm or more inward from the circumferential surface of the covering portion, and in that portion, the end of the cylindrical body forms an exposed portion that is exposed from the covering portion. The optical instrument according to claim 11 or 12, characterized in that it is a feature of the optical instrument according to claim 11 or 12.

14. The cylindrical body includes a resin layer having a thickness of 50 μm or more and 200 μm or less, which is provided on the side opposite to the first carbon fiber layer relative to the second carbon fiber layer. The optical instrument according to any one of claims 1 to 13.

15. The optical instrument according to any one of claims 1 to 14, characterized in that the cylindrical body constitutes at least one of a lens hood, a lens barrel body, and a focus ring.

16. The optical instrument according to any one of claims 1 to 15, characterized in that it is a camera interchangeable lens.

17. The optical instrument according to any one of claims 1 to 16, characterized in that it is a telephoto lens with a focal length exceeding 300 mm.

18. A method for manufacturing an optical instrument, which includes an optical element and a lens barrel for holding or adjusting the optical element, The manufacturing process for the cylindrical body which is a lens barrel component of the aforementioned optical instrument is as follows: A step of forming a first carbon fiber layer impregnated with a first thermoplastic resin on a mandrel, A step of forming a second carbon fiber layer impregnated with a second thermoplastic resin on the first carbon fiber layer on the mandrel, The process includes heating the first thermoplastic resin and the second thermoplastic resin to fix the first carbon fiber layer and the second carbon fiber layer together. In the step of forming the first carbon fiber layer, the first carbon fiber layer is a braided layer in which a plurality of carbon fibers of the first carbon fiber layer are assembled in a tubular shape at an inclination with respect to the axial direction of the tubular body, and which is provided in an endless manner in the circumferential direction of the tubular body. A manufacturing method characterized in that, in the step of forming the second carbon fiber layer, the second carbon fiber layer is a braided layer in which a plurality of carbon fibers of the second carbon fiber layer are assembled in a tubular shape with inclination with respect to the axial direction of the tubular body, and which is provided in an endless manner in the circumferential direction of the tubular body.

19. The fixing step is performed with the third carbon fiber layer positioned between the first carbon fiber layer and the second carbon fiber layer. The manufacturing method according to claim 18, characterized in that it

20. The third carbon fiber layer is impregnated with a thermoplastic resin. The manufacturing method according to claim 19, characterized by the features described above.

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