Lens barrel, optical apparatus, and image pickup apparatus

A lens barrel includes an optical element, a holding member configured to hold the optical element on an inner surface of the holding member, and an adhesive with which a side surface of the optical element and the inner surface of the holding member are adhered to each other. A hole is formed in the holding member from an outer surface toward the inner surface of the holding member. The adhesive is injected in the hole. A groove is formed in the inner surface of the holding member. The groove communicates with the hole. A fitting portion on the inner surface of the holding member disposed on an outer side of the groove is fitted to the side surface of the optical element.

BACKGROUND OF THE DISCLOSURE

Field of the Disclosure

The disclosure relates to a lens barrel, an optical apparatus, and an image pickup apparatus.

Description of the Related Art

There has been known a lens barrel in which an optical element is bonded to a holding member with an adhesive. In Japanese Patent Application Laid-Open No. H01-238612, the following lens barrel is disclosed. Specifically, a holding member has an injection port for an adhesive on an outer peripheral portion thereof and an adhesive groove in an inner peripheral portion thereof. An adhesive is poured into the adhesive groove from the injection port, thereby bonding an optical element to the holding member.

In the configuration disclosed in Japanese Patent Application Laid-Open No. H01-238612, when the adhesive is injected from the injection port of the holding member, the adhesive may leak from a gap between the optical element and the holding member.

SUMMARY OF THE DISCLOSURE

An aspect of embodiments provides, for example, a lens barrel beneficial in an optical element being adhered thereto with an adhesive.

An aspect of embodiments provides a lens barrel including: an optical element; a holding member configured to hold the optical element on an inner surface of the holding member; and an adhesive with which a side surface of the optical element and the inner surface of the holding member are adhered to each other, wherein a hole is formed in the holding member from an outer surface toward the inner surface of the holding member, the adhesive being injected in the hole; a groove is formed in the inner surface of the holding member, the groove communicating with the hole; and a fitting portion on the inner surface of the holding member disposed on an outer side of the groove is fitted to the side surface of the optical element.

According to the present disclosure, it is possible to provide a lens barrel which is advantageous in bonding an optical element with an adhesive, for example.

DESCRIPTION OF THE EMBODIMENTS

First Embodiment

Now, a first embodiment of the present disclosure is described.FIG.1is a sectional view of a state in which a holding lens barrel2(holding member) according to the first embodiment holds an optical system1(optical element) on an inner surface thereof.FIG.2is a perspective view of the holding lens barrel2having a cylindrical shape. Further, in the drawings, a front-and-rear direction is defined along an optical axis O, a left side corresponds to a front side, and a right side corresponds to a rear side.

The holding lens barrel2includes two fitting portions2aand2b, an adhering groove2g(groove), and a screwing portion2don an inner surface thereof. The two fitting portions2aand2bare fitted to an outer peripheral surface1a(side surface) extending along a circumference of the optical system1. An adhesive A is injected into the adhering groove2g. A pressing ring3(pressing member) configured to fix the optical system1is threadedly engaged with the screwing portion2d. The fitting portions2aand2bextend along a circumference of the holding lens barrel2, and may extend annularly over the entire circumference. Further, the holding lens barrel2includes an abutment portion2cagainst which one surface1cof the optical system1is to be brought into abutment when the optical system1is fitted into the holding lens barrel2.

The adhering groove2gis formed between the two fitting portions2aand2bin a direction of the optical axis O. The adhering groove2gextends along the circumference of the holding lens barrel2, and may extend over the entire circumference of the holding lens barrel2. That is, the two fitting portions2aand2bare formed on the inner surface on the outer side of the adhering groove2g. Further, a plurality of holes2hconfigured to allow injection of the adhesive A into the adhering groove2gare formed from an outer surface2fto the inner surface of the holding lens barrel2, and those holes2hallow communication between the outer surface2fand the adhering groove2gof the holding lens barrel2. The plurality of holes2hare arranged, thereby being capable of freely selecting a hole2hto inject the adhesive A at the time of assembly operation.

Next, assembly and bonding and fixing of the optical system1to the holding lens barrel2are described. The optical system1is fitted into the holding lens barrel2along the direction of the optical axis O until the one surface1cof the optical system1is brought into abutment against the abutment portion2cof the holding lens barrel2. When the optical system1is fitted, the outer peripheral surface1aof the optical system1is fitted to the two fitting portions2aand2bof the holding lens barrel2. Then, the pressing ring3is fitted into the screwing portion2dof the holding lens barrel2along the direction of the optical axis O. When the pressing ring3is brought into abutment against another surface1bof the optical system1, the optical system1is positioned in the direction of the optical axis O.

With such threaded engagement of the pressing ring3, the optical system1is sandwiched by the holding lens barrel2and the pressing ring3. A lens barrel includes one or a plurality of holding lens barrels2each holding the optical system1as described above. After the pressing ring3is threadedly engaged, the adhesive A is filled in the adhering groove2gformed in the inner surface of the holding lens barrel2from the holes2hformed in the outer surface2fof the holding lens barrel2. The adhesive A is received in the holes2hand the adhering groove2g, thereby bonding and fixing the optical system1to the holding lens barrel2. With the configuration using the pressing ring3, the optical system1is sandwiched by the holding lens barrel2, but may be sandwiched by, for example, caulking as long as the position of the optical system1with respect to the holding lens barrel2in the direction of the optical axis O can be substantially fixed. In the case of caulking, the adhesive A is filled in the adhering groove2gfrom the holes2hafter the caulking is performed, thereby obtaining the same effect.

With the above-mentioned configuration, the adhesive A is filled in the adhering groove2gextending over the entire circumference of the holding lens barrel2. Thus, the bonding area is increased to improve the adhesive strength, thereby obtaining an effect of suppressing positional displacement of the optical system1with respect to the holding lens barrel2when an impact is applied.

Further, the adhesive A is filled in a space defined by the outer peripheral surface1aof the optical system1and the adhering groove2g. The adhering groove2gis formed between the two fitting portions2aand2bapart from each other in the front-and-rear direction of the optical axis O. Thus, the fitting portions2aand2bhave an effect of preventing outflow of the adhesive A. Moreover, the fitting portions2aand2bare annularly formed, and each have a protrusion shape protruding in a radial direction which is a direction orthogonal to the direction of the optical axis O, thereby being capable of further reducing the outflow of the adhesive A. As a result, an influence on optical performance due to the outflow of the adhesive A or a wiping process for the adhesive A is reduced, thereby being capable of improving assembly operability. The two fitting portions2aand2bare formed along the direction of the optical axis O, but the outflow of the adhesive A can be prevented even with at least one fitting portion.

In the first embodiment, the holes2hconfigured to allow injection of the adhesive A are round through holes, but the shape is not limited thereto. As long as the holes2hpass through the adhering groove2gand the outer surface2fof the holding lens barrel2, the adhesive A can be injected. Thus, for example, the holes2hmay be elongated through holes each having a width in the circumferential direction, thereby being capable of improving operability for filling the adhesive A.

Further, in the first embodiment, the adhering groove2gis a groove extending over the entire circumference. However, it is only required that the fitting portions2aand2bbe formed at the front and back in the direction of the optical axis O, and the shape of the groove is not limited thereto. For example, with a groove having a length that can secure the bonding area required to hold the optical system1, processing time for the holding lens barrel2is shortened, thereby being capable of reducing component cost. Similarly, in the first embodiment, the plurality of holes2hconfigured to allow injection of the adhesive A are formed. However, with at least one hole2h, the adhesive A can be injected into the adhering groove2g. For example, the number of the holes2hinto which the adhesive A is injected is reduced, and the processing time for the holding lens barrel2is reduced, thereby being capable of reducing the component cost, for example.

Second Embodiment

FIG.3is a partial sectional view of a holding lens barrel22according to a second embodiment. In the following, configurations different from those of the first embodiment are described, and description of the same configurations as those of the first embodiment is omitted. Fitting portions22aand22bformed on an inner surface of the holding lens barrel22are fitted to an outer peripheral surface21a(side surface) of an optical system21, and the fitting portions22aand22beach have a V groove22e(groove) having a substantially V shape. With such a configuration, even when the adhesive A intrudes between the fitting portions22aand22band the outer peripheral surface21aof the optical system21, the adhesive A accumulates in the V grooves22e, thereby being capable of preventing the adhesive A from permeating surfaces21band21cof the optical system21. That is, the V grooves22eeach function as an accumulating portion (accumulator; accumulating pool) for the leaked adhesive A.

Third Embodiment

FIG.4is a partial sectional view of a holding lens barrel32according to a third embodiment. In the following, configurations different from those of the first embodiment are described, and description of the same configurations as those of the first embodiment is omitted. Fitting portions32aand32bof the holding lens barrel32each have a shape inclined with respect to the direction of the optical axis O (tapered portion). An outer peripheral surface31a(side surface) of an optical system31also has a shape inclined corresponding to the fitting portions32aand32b, and the fitting portions32aand32bare fitted to the outer peripheral surface31aof the optical system31. In assembly, when the optical system31is inserted into the holding lens barrel32, the outer peripheral surface31aand the fitting portions32aand32bcome in contact with each other, thereby being capable obtaining the same effect as that of the first embodiment. Further, with such a configuration, the outer peripheral surface31ais positioned along the fitting portions32aand32b, thereby also obtaining an effect of allowing the center axes of the optical system31and the holding lens barrel32to easily match each other.

In each embodiment of the present disclosure, the interchangeable lens configured to perform still image and moving image photography has been described, but the same effect may be obtained in a lens barrel that is interchangeable such as a projection lens or an optical element for a copying machine. Further, a lens barrel to which the present disclosure is applied is used for an image pickup apparatus including an image pickup element configured to pick up an image formed by a lens barrel or an image pickup system including an image pickup apparatus main body including an image pickup element and having a lens barrel removably mounted thereto. Further, the present disclosure can be applied also to a lens integrated image pickup apparatus.

The preferred embodiments of the present disclosure have been described above. The present disclosure is not limited to those embodiments, and various modifications and changes can be made thereto within the scope of the gist of the present disclosure. Further, when an optical apparatus including the lens barrel of the present disclosure and an image pickup apparatus including the optical apparatus are achieved, the optical apparatus and the image pickup apparatus that provide the effect of the present disclosure can be achieved.

This application claims the benefit of Japanese Patent Application No. 2020-070661, filed Apr. 9, 2020, which is hereby incorporated by reference herein in its entirety.