JP5317890B2 - Lens barrel - Google Patents

Description

  The present invention relates to a lens barrel having a lens frame that accommodates and holds a lens group.

  2. Description of the Related Art Conventionally, a lens barrel having a lens frame that accommodates and holds a lens group composed of a plurality of lenses is widely known.

  For example, in the lens barrel of Patent Document 1 below, each lens of the lens group is fixed by a pressing member in a state of being accommodated in a lens frame. Further, in the lens barrel of Patent Document 2 below, lenses are inserted from both sides of the lens frame along the optical axis, and are fixed by heat caulking.

JP 2001-350073 A JP 2001-051175 A

  However, in the lens barrel of the above-mentioned Patent Document 1, since it is necessary to screw in with a pressing member while interposing a space ring between the lenses, it is not easy to fix the lens, and the number of parts increases. Further, the lens barrel of Patent Document 2 has a configuration in which the lens is assembled by heat caulking from both sides of the lens frame. For this reason, it is necessary to provide a contact surface for positioning each lens on both sides in the optical axis direction and a heat caulking part, which requires a lot of space for fixing the lens and leads to an increase in the diameter of the lens and the lens frame. Also, maintaining the optical axis accuracy is not easy.

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a lens barrel that can reduce the space required for fixing the lens and improve the workability of fixing the lens. There is to do.

  In order to achieve the above object, a lens barrel of the present invention accommodates and holds a lens group consisting of a plurality of lenses and the lens group, and a first opening is formed on one side along the optical axis of the lens group. And a lens frame having a second opening larger than the first opening formed on the other side along the optical axis, and the lens frame includes the first lens group in the lens group. A thrust receiving surface is formed that contacts a lens disposed near the opening of the lens and restricts the position of the lens in the direction along the optical axis, and the thrust receiving surface from the outside of the first opening. A through hole for applying an adhesive to the thrust receiving surface is formed to be connected to the thrust receiving surface.

  According to the present invention, it is possible to reduce the space required for fixing the lens and improve the workability of fixing the lens.

It is a longitudinal cross-sectional view of the lens barrel which concerns on one embodiment of this invention. It is the figure which looked at the lens frame from the 2nd opening side. It is an enlarged view of the A section of FIG. It is the perspective view which looked at the lens frame cut | disconnected along the optical axis from the 2nd opening side. It is a disassembled perspective view of a lens frame and a 1st lens. It is the perspective view which looked at the lens frame with which the 1st lens was assembled | attached from the 1st opening side. It is a perspective view of the lens frame cut | disconnected along the optical axis which shows the fixing method of the 1st lens using a jig | tool.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the configuration of a lens barrel according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a longitudinal sectional view of the lens barrel. This lens barrel has a lens frame 21, and the lens group 14 is accommodated and held in the lens frame 21. The lens group 14 includes a first lens 11, a second lens 12, and a third lens 13, and these lenses are disposed so as to have a common optical axis 1. The lens frame 21 has a first opening 26 on one side along the optical axis 1 (right side in the figure) and a second opening 27 on the other side along the optical axis 1 (left side in the figure). Is formed. The lenses 11, 12, and 13 are arranged in this order from the side close to the first opening 26.

  The third lens 13 has the largest outer diameter of the lens group 14, and the first lens 11 has the smallest outer diameter. The second opening 27 is larger than the first opening 26, and has a size and shape that allows all the lenses 11, 12, and 13 to be inserted. The diameter of the first opening 26 is smaller than the outer diameter of the first lens 11.

  FIG. 2 is a view of the lens frame 21 as viewed from the second opening 27 side. FIG. 3 is an enlarged view of part A in FIG. FIG. 4 is a perspective view of the lens frame 21 cut along the optical axis 1 as seen from the second opening 27 side.

  The lens frame 21 is integrally formed with a thrust receiving surface 22 and a radial receiving surface 23 as a “holding portion” for holding the first lens 11 (see FIGS. 1, 2, and 4). The holding parts for the first lens 11 are close to the first opening 26, and the same configuration is provided at three equal intervals in the circumferential direction around the optical axis 1 which is also the central axis of the lens frame 21. (See FIG. 2).

  The thrust receiving surface 22 is a flat surface perpendicular to the optical axis 1. The radial receiving surface 23 is an arc-shaped surface that slightly protrudes toward the inner peripheral side of the lens frame 21 (see FIG. 3). In the circumferential direction around the optical axis 1, the thrust receiving surface 22 and the radial receiving surface 23 are in phase with each other. The first lens 11 is positioned in the thrust direction (the direction along the optical axis 1) by contacting the thrust receiving surface 22. Further, the first lens 11 is positioned in the radial direction by press-fitting the outer peripheral surface of the first lens 11 to the radial receiving surface 23.

  As shown in FIGS. 1, 3, and 4, a fixing hole 24 that is a through hole is formed to be connected to a portion of each holding portion where the radial receiving surface 23 and the thrust receiving surface 22 are connected. . The fixing hole 24 communicates with the inside of the lens frame 21 and the outside on the first opening 26 side. The phase of the fixing hole 24 coincides with the thrust receiving surface 22 and the radial receiving surface 23.

  With respect to the radial direction of the first lens 11, each fixing hole 24 is formed from a position on the inner side (optical axis 1 side) of the corresponding inner surface of the radial receiving surface 23 to a position on the outer side of the inner surface of the radial receiving surface 23. (See FIGS. 1 and 3). With respect to the circumferential direction around the optical axis 1, the fixing holes 24 are formed in a range shorter than the arc length of the corresponding radial receiving surface 23 (see FIG. 3).

  As shown in FIG. 1, in a state where the first lens 11 is held by the lens frame 21, the fixing hole 24 is blocked by the first lens 11. Therefore, while the first lens 11 is not held, the inside of the lens frame 21 is visible from the first opening 26 side, but when the first lens 11 is held, the first opening 11 side is visible. The first lens 11 itself is visible (see also FIGS. 6 and 7).

  As shown in FIG. 1, on the inner surface of the lens frame 21, the second lens 12 is located closer to the second opening 27 than the holding portion (thrust receiving surface 22, radial receiving surface 23) for the first lens 11. A holding portion (thrust receiving surface 32, radial receiving surface 33) is formed. The thrust receiving surface 32 and the radial receiving surface 33 are provided at three positions with the same phase and at equal intervals in the circumferential direction around the optical axis 1.

  On the inner surface of the lens frame 21, closer to the second opening 27 than the holding portion for the second lens 12 (thrust receiving surface 32, radial receiving surface 33), the holding portion for the third lens 13 (thrust receiving). A surface 42 and a radial receiving surface 43) are formed. The thrust receiving surface 42 and the radial receiving surface 43 are provided at three locations with the same phase and at equal intervals in the circumferential direction around the optical axis 1.

  The thrust receiving surfaces 32 and 42 are flat surfaces, and their directions are the same as those of the thrust receiving surface 22. The radial receiving surfaces 33 and 43 are arcuate surfaces like the radial receiving surface 23.

  The second lens 12 is positioned in the thrust direction by coming into contact with the thrust receiving surface 32, and is positioned in the radial direction by press-fitting the outer peripheral surface to the radial receiving surface 33. The third lens 13 is positioned in the thrust direction by abutting against the thrust receiving surface 42 via the annular sheet 44, and the outer peripheral surface is press-fitted and fitted into the radial receiving surface 43, thereby positioning in the radial direction. Made.

  Since the radial receiving surfaces 23, 33, and 43 are concentric, the positions of the lenses 11, 12, and 13 are concentrically controlled, and the accuracy of the common optical axis 1 is maintained. The radial receiving surface 43 constitutes a part of the second opening 27 (see FIGS. 2 and 4).

  Next, a method for fixing the first lens 11 will be described with reference to FIGS.

  FIG. 5 is an exploded perspective view of the lens frame 21 and the first lens 11. FIG. 6 is a perspective view of the lens frame 21 to which the first lens 11 is assembled as viewed from the first opening 26 side. FIG. 7 is a perspective view of the lens frame 21 cut along the optical axis 1 showing a method of fixing the first lens 11 using a jig.

  When the first lens 11 is housed and fixed in the lens frame 21, first, the flat surface of the first lens 11 is directed to the second opening 27, and the second opening is formed along the lens insertion direction 41 (FIG. 5). The first lens 11 is inserted from 27 to the position of the thrust receiving surface 22.

  Next, from the first opening 26 side, UV adhesive is applied to the thrust receiving surface 22 and the radial receiving surface 23 through the fixing hole 24, and the first lens 11 is bonded and fixed by irradiating ultraviolet rays (see FIG. 6). ). As described above, since the same number of thrust receiving surfaces 22, radial receiving surfaces 23, and fixing holes 24 are provided in the same phase, the fixing holes 24 are closed by the first lens 11. In particular, since the radial receiving surface 23 and the thrust receiving surface 22 are connected to each other, and the fixing hole 24 is formed so as to be connected to the radial receiving surface 23 and the thrust receiving surface 22, the first lens 11 is connected to the radial receiving surface 23 and the thrust receiving surface 22. When contacted, the fixing hole 24 is closed without a gap.

  Therefore, it is possible to prevent the applied adhesive from flowing into the gap between the first lens 11 and the lens frame 21 more than necessary, and it is possible to reduce the occurrence of ghost, flare, etc. due to uncured or flowing of the adhesive. Further, dust can be prevented from entering the lens frame 21.

  Here, as shown in FIG. 7, the first lens 11 is held on the jig 51, the lens frame 21 is covered from above the first lens 11, and UV adhesive is applied through the fixing hole 24 to apply the first lens 11. A method of fixing the lens 11 may be taken. By doing so, it is not necessary to change the direction of the lens frame 21 in the process from the insertion to the fixing of the first lens 11, and the operation is easy.

  On the other hand, after the first lens 11 is fixed, the second lens 12 is inserted into the lens frame 21 through the second opening 27 and is brought into contact with and engaged with the thrust receiving surface 32 and the radial receiving surface 33. Then, for example, the second lens 12 is fixed by heat caulking. The third lens 13 is inserted into the lens frame 21 through the second opening 27 together with the annular sheet 44 after the second lens 12 is fixed, and is brought into contact with and engaged with the thrust receiving surface 42 and the radial receiving surface 43. . At that time, the UV adhesive is applied between the thrust receiving surface 42, the radial receiving surface 43, and the third lens 13 and the annular sheet 44. Thereafter, it is fixed by irradiating with ultraviolet rays. The annular sheet 44 may be bonded to the third lens 13 in advance, and the annular sheet 44 is not essential.

  If the first lens 11 is also fixed by heat caulking, it is necessary to secure a space for heat caulking in the lens frame 21, and the first lens 11 to the lens frame 21 become larger. However, in the present embodiment, the first lens 11 is fixed by adhesion, and the fixing hole 24 is provided in a state in which the first lens 11 can be visually observed, so that the adhesive is applied from the first opening 26 side. Can be applied. Therefore, it is not necessary to shift the phase so that the holding portions of the lenses do not overlap for fixing the lens. For this reason, an increase in the outer diameter of the lens frame 21 is avoided. In addition, since the first lens 11 can be fixed by applying an adhesive from the outside of the lens frame 21, workability is dramatically improved.

  According to the present embodiment, the fixing hole 24 for applying the adhesive to the thrust receiving surface 22 from the outside of the first opening 26 is formed so as to be connected to the thrust receiving surface 22. Thereby, the space required for fixing the first lens 11 can be reduced, and the workability of fixing the first lens 11 can be improved.

  Further, since all of the lens group 14 is inserted into the lens frame 21 from the second opening 27 along the lens insertion direction 41 (FIG. 5), it is easy to ensure the accuracy of the lens frame 21 and the optical axis 1. The accuracy is easily ensured.

  Furthermore, in the state where the lens group 14 is held by the lens frame 21, the fixing hole 24 is blocked by the first lens 11, so that uncured or flowing adhesive and intrusion of dust can be suppressed.

  The present invention is not limited to the above embodiment, and various modifications and changes can be made within the scope of the gist.

  For example, the thrust receiving surface 22 for positioning the first lens 11 in the direction of the optical axis 1 is not limited to the illustrated shape.

  Further, as the positioning mechanism in the radial direction of the first lens 11, the fitting of the radial receiving surface 23 and the first lens 11 is illustrated, but a gap is provided so that alignment can be performed to improve optical performance depending on the lens configuration. May be provided. Further, the radial receiving surface 23 is not limited to this shape as long as the optical performance of the first lens 11 can be maintained.

  Further, the method for holding and fixing the second lens 12 and the third lens 13 to the lens frame 21 is not limited to the exemplified one. However, when heat caulking is adopted, a material suitable for heat caulking such as resin is adopted as the material of the lens frame 21.

  There are three holding portions for the lenses 11, 12, and 13 in the circumferential direction, but there may be four or more holding portions. The holding unit for the second lens 12 does not need to be in phase with the holding unit for the first lens 11.

  Further, although UV adhesive is used for fixing the first lens 11 and the second lens 12, other adhesives may be used as long as they can be fixed to the lens frame 21.

  Further, the number of lenses constituting the lens group 14 may be plural, and may be four or more.

DESCRIPTION OF SYMBOLS 1 Optical axis 11 1st lens 14 Lens group 21 Lens frame 22 Thrust receiving surface 23 Radial receiving surface 24 Fixing hole 26 1st opening 27 2nd opening

Claims (4)

A lens group consisting of a plurality of lenses;
The lens group is accommodated and held, and a first opening is formed on one side along the optical axis of the lens group, and a second opening larger than the first opening on the other side along the optical axis. And a lens frame formed with
The lens frame is formed with a thrust receiving surface that abuts a lens disposed closest to the first opening in the lens group and restricts the position of the lens in the direction along the optical axis. And a through-hole for applying an adhesive to the thrust receiving surface from the outside of the first opening is formed so as to be connected to the thrust receiving surface.   2. The lens according to claim 1, wherein the second opening is formed to a size that allows the entire lens group to be inserted into the lens frame from the second opening. A lens barrel.   In the state where the lens arranged closest to the first opening in the lens group is in contact with the thrust receiving surface and held by the lens frame, the lens closes the through hole. The lens barrel according to claim 1 or 2, wherein   The lens frame is formed with a radial receiving surface that abuts an outer peripheral surface of a lens disposed closest to the first opening in the lens group and regulates a radial position of the lens, The circumferential direction centering on an optical axis WHEREIN: The said thrust receiving surface and the said radial receiving surface were provided in the several location in the same phase, The any one of Claims 1-3 characterized by the above-mentioned. The lens barrel described.