JP-7855754-B2 - Optical instruments, methods for manufacturing optical instruments

JP7855754B2JP 7855754 B2JP7855754 B2JP 7855754B2JP-7855754-B2

Inventors

菊池渉

Assignees

キヤノン株式会社

Dates

Publication Date: 20260508
Application Date: 20250311
Priority Date: 20180427

Claims (20)

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.
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.
The first carbon fiber layer and the third carbon fiber layer are fixed together by the resin impregnated into the first carbon fiber layer , and the second carbon fiber layer and the third carbon fiber layer are fixed together by the resin impregnated into the second carbon fiber layer . The optical instrument according to claim 1 or 2.
The aforementioned third carbon fiber layer is a braided layer. The optical instrument according to any one of claims 1 to 3.
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.
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.
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.
The thermoplastic resin is polycarbonate. The optical instrument according to feature 7.
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.
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.
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.
The resin of the coating is a thermoplastic resin containing fibers, and/or the resin of the coating is polycarbonate. The optical instrument according to feature 11.
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.
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.
The optical instrument according to any one of claims 1 to 14, characterized in that the cylindrical body constitutes at least one of the following: a lens hood, a lens barrel body, and a focus ring.
An optical instrument according to any one of claims 1 to 15, characterized in that it is a camera lens.
An optical instrument according to any one of claims 1 to 16, characterized by being a telephoto lens with a focal length exceeding 300 mm.
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.
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
The third carbon fiber layer is impregnated with a thermoplastic resin. The manufacturing method according to claim 19, characterized by the features described above.

Description

This invention relates to a lens barrel component, an optical instrument, and a method for manufacturing a lens barrel component, all constructed from carbon fiber reinforced resin. Traditionally, interchangeable camera lenses, such as telephoto lenses with focal lengths exceeding 300mm, have been large and weighed in the order of kilograms. Even for optical equipment in this focal length range, there is a demand for lightweight and high-strength products that are easy to carry and improve operability during shooting. Traditionally, the lens barrels of large optical instruments of this type were made of aluminum alloy or magnesium alloy for their impact resistance. Similarly, the lens hoods attached to these lenses were also made of aluminum alloy for impact resistance. However, even though these metal materials belong to the category of light metals, there were limits to how much weight reduction could be achieved. Therefore, in recent years, the use of carbon fiber reinforced polymer (CFRP), which is made by impregnating carbon fibers with thermosetting resins such as epoxy, to manufacture telescope tubes and lens hoods has been considered. When manufacturing telescope tube components using CFRP, for example, the shape is formed using a method called the 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. Afterward, the carbon fibers are impregnated and cured with a thermosetting resin such as epoxy using an autoclave or similar method. 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. Therefore, to solve this problem, a proposed configuration involves laminating unidirectional prepreg sheets in single or multiple layers in both the axial and circumferential directions of the lens barrel, and then wrapping the final circumferential unidirectional prepreg sheet around the outside of the axial unidirectional prepreg sheet to achieve impact resistance (see Patent Document 1 below). Patent No. 4813619 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.This is a perspective view showing a braiding device according to an embodiment of the present invention.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.The following diagrams illustrate different structures of the cylindrical body according to embodiments of 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 showing a part of the cylindrical body.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.(a) to (d) are explanatory diagrams showing the insert molding process for a cylindrical body according to an embodiment of the present invention.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.(a) to (d) are explanatory diagrams showing the insert molding process for a cylindrical body according to an embodiment of the present invention.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. The following describes embodiments for carrying out the present invention with reference to the attached drawings. Note that the configurations shown below are merely examples, and 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. <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