JP5156587B2 - Lens movement frame - Google Patents

Description

  The present invention relates to a lens moving frame that is incorporated in a lens device so as to be movable by a cam cylinder.

  A zoom lens device used in a camera or projector incorporates a plurality of lens groups in one lens and can change the relative position to set the focal length to a desired zoom value. Each lens group includes at least one lens and an annular lens frame that supports the lens. For example, three cam followers are provided on the outer periphery of the lens frame. The cam follower engages with a linear cam groove provided on the fixed cylinder and a rotating cam groove provided on a cam ring that rotates relative to the fixed cylinder, and is positioned by the relative position of the two cam grooves. The lens frame is moved along the optical axis direction by sliding on the cam surface of the groove.

Zoom lens barrels with a combination of multiple lenses have a very high accuracy in mounting the cam follower to the lens frame or the dimensional accuracy between the lens frames. You may be forced to rework. However, reassembly is not easy, and in most cases, a lens frame, a cylindrical member, and the like must be newly replaced. In Patent Document 1 below, as a configuration for adjusting the distance between the front lens group and the rear lens group, a coupling member is provided on the lens frame of the rear lens group, and a spacer is used between the lens frame and the coupling member of the rear lens group. A method of fixing an adjusted interval by bonding a spacer to a connecting member is shown. Patent Document 2 below describes a lens moving frame in which a cam follower mounting portion is separated from a lens storage portion.
JP-A-10-319292 JP 2006-023359 A

  If the cam follower is attached to the lens frame at a slight angle, the lens frame is inclined and attached to the lens barrel, so that the lens frame cannot be used. It is necessary to remove the cam follower attached diagonally from the lens frame and reattach it correctly. However, since the cam follower is screwed to the lens frame using a tapping screw, etc. The pilot hole becomes stupid and the cam follower is not fixed correctly to the lens frame. Alternatively, even if it seems to be correctly fixed, it is not firmly fixed, so that when it is used, play occurs immediately and the predetermined optical accuracy cannot be maintained. Like the method disclosed in the above-mentioned patent document, the method of replacing a defective member by configuring a plurality of members between the cam follower and the lens frame is not only complicated in structure but also used once. The discarded parts must be discarded.

  In order to solve the above problems, the present invention provides a zoom lens moving frame that can be redone without discarding one component even if the cam follower fails to be attached to the lens frame.

In the lens moving frame according to the present invention, three cam followers that hold the lens and engage with cam grooves formed in the cam cylinder are attached to the outer peripheral surface, and are moved in the optical axis direction by the rotation of the cam cylinder. In the lens moving frame, one set of three mounting holes used when the three cam followers are attached to the outer peripheral surface, and a shift from the mounting hole in the outer peripheral direction, the same shape as the mounting hole, One set of three or more spare mounting holes having the same hole interval is provided .

The lens moving frame is provided at a position where the set of three attachment holes equally divides the outer periphery for each set. The cam follower includes a shaft member that is assembled in the mounting hole so as to be perpendicular to the optical axis of the lens, and a cam roller that is rotatably supported by the shaft member and engages with the cam groove. A fixed cylinder provided coaxially with the cam cylinder is provided with N straight guide grooves extending in parallel with the optical axis, and guide rollers engaged with the straight guide grooves are rotatably supported on the shaft members. Is done. The shaft member is a tapping screw that is screwed into the lens moving frame using the mounting hole as a guide. A receiving surface parallel to the optical axis is formed on the outer peripheral surface so as to surround the mounting hole, and the tapping screw is crimped to the receiving surface when the tapping screw is screwed into the mounting hole perpendicularly to the optical axis. A crimping surface to be formed is formed .

  Since the lens moving frame of the present invention is provided with mounting holes that are integral multiples of the number of cam followers that can be mounted on the lens frame, even if mounting of one cam follower fails, another mounting hole may be used. Thus, it is possible to provide a zoom lens moving frame that is space-saving and low-cost.

  As shown in FIG. 1, the zoom lens apparatus 10 includes a fixed cylinder 12 having a first lens group 11 that performs focusing, and a gear unit 13 that is housed inside the fixed cylinder 12 and rotated by a driving device (not shown). The cam cylinder 14 is configured. A helicoid gear (not shown) is formed on the first lens frame 15 in which the first group lens 11 is housed, and is screwed with a helicoid gear (not shown) formed on the fixed cylinder 12. Focusing is performed by turning 15. The fixed cylinder 12 has straight guide grooves (hereinafter referred to as “guide grooves”) 17 formed at three locations that divide the rotation direction into three equal parts around the optical axis 16. The cam barrel 14 is provided with a set of three rotating cam grooves (hereinafter referred to as cam grooves) 18 that are curved at three locations that divide the rotation direction into three equal parts around the optical axis 16. Inside the cam barrel 14, a lens moving frame 20 for holding second, third, and fourth group lenses (hereinafter referred to as a variable power lens) 19 (refer to FIG. 3) for changing the focal length by thermal caulking. Is placed.

  As shown in FIGS. 2 and 3, the lens moving frame 20 has three cam followers 21 attached to three portions that are divided into three equal parts around the optical axis 16 on the outer peripheral surface 20 a. The cam follower 21 includes a guide roller 22 that engages with the guide groove 17, a cam roller 23 that engages with the cam groove 18, and a tapping screw 24 that attaches the guide roller 22 and the cam roller 23 to the lens moving frame 20. The tapping screw 24 is formed on a shaft portion 24a that rotatably supports the guide roller 22 and the cam roller 23 on the lens moving frame 20, and a pressure contact surface 24b of the shaft portion 24a. And a screw portion 24c screwed into the hole 32 (see FIG. 4).

  As shown in FIG. 4, the lens moving frame 20 has a lens space 28 that encloses and holds the variable magnification lens 19 at the center, and three cam followers mounted at three locations that divide the outer peripheral surface 20a into three equal parts. One set of bosses 31 is formed, and a mounting hole 32 into which the screw portion 24c of the tapping screw 24 is screwed is formed in the center. Around the mounting hole 32, a receiving surface 34 that fixes the pressure-bonding surface 24 b so that the shaft portion 24 a is perpendicular to the optical axis 16 when the screw portion 24 c is screwed into the mounting hole 32. And a rib 35 is formed outside the receiving surface 34. By attaching the shaft portion 24 a to each of the attachment holes 32 so as to be perpendicular to the optical axis 16, the cam roller 23 rotatably supported by the shaft portion 24 a is also attached perpendicularly to the optical axis 16. Smooth movement of the lens moving frame 20 is ensured. Three cam follower mounting bosses 31 having spare mounting holes 33 are formed at positions rotated by 60 ° in the same direction from the three cam follower mounting bosses 31, respectively. A receiving surface 34 is provided in the center of the spare mounting hole 33.

  As shown in FIG. 5, the zoom lens device 10 is used by being incorporated in a projector 40, for example. The projector 40 includes a zoom lens apparatus 10 that employs the lens moving frame 20 according to the present invention, a light source 43, an illumination optical system 44, a total reflection prism 45, and a digital micromirror device (hereinafter referred to as a DMD). .) 46 is accommodated, and when the cam cylinder 14 provided in the zoom lens device 10 is rotated, the cam groove 18 moves the cam follower 21 in the direction of the optical axis 16, and the focal length of the zoom lens device 10 is increased. It is adjusted to change the size of the projected image. The light emitted from the light source 43 passes through an illumination optical system 44 including a color filter, an integrator, and the like, enters the total reflection prism 45, and the image displayed on the DMD 46 is projected onto a screen or the like by the zoom lens device 10. . As the light source 43, a high-intensity discharge lamp such as an ultra-high pressure mercury lamp, a metal halide lamp, or a xenon lamp is generally used. The illumination optical system 44, the total reflection prism 45, and the DMD 46 in the above configuration are well-known techniques and will not be described. In the zoom lens device 10, the fixed cylinder 12 is fixed to a front plate 41 a of the housing 41 with screws, and a gap between the front plate 41 a and the fixed cylinder 12 is covered with a decorative ring 47.

  Next, the operation of the above embodiment will be described. As shown in FIGS. 1 and 3, the positions of the three attachment holes 32 formed on the outer peripheral surface 20a of the lens moving frame 20 are aligned with the guide groove 17 and the cam groove 18 overlapping with each other, Each of the cam followers 21 is inserted into the cam follower mounting boss 31 provided with a mounting hole 32 in order. As shown in FIG. 4, after the guide roller 22 and the cam roller 23 are sequentially inserted through the shaft portion 24a, the screw portion 24c is inserted into the mounting hole 32, and the crimping surface 24b of the tapping screw 24 is the receiving surface. Screw in until 34. As a result, the tapping screw 24 is vertically attached to the receiving surface 34, so that the tapping screw 24 is also perpendicularly attached to the optical axis 16, and is rotatably attached to the shaft portion 24a of the tapping screw 24. The guide roller 22 and the cam roller 23 are also attached so that the rotation axis is perpendicular to the optical axis 16, and are fitted in the guide groove 17 and the cam groove 18, respectively.

  When the screw portion 24 c of the tapping screw 24 is screwed into the mounting hole 32 and the crimping surface 24 b of the tapping screw 24 is crimped to the receiving surface 34, the tapping screw 24 is inclined with respect to the receiving surface 34. In the case where the cam follower 21 is attached to the lens moving frame 20, the tapping screw 24 is rotated in the reverse direction to remove the cam follower 21 from the lens moving frame 20. All the cam followers 21 already attached to the same lens moving frame 20 are also removed. The lens moving frame 20 from which the cam follower 21 has been removed is rotated by 60 °, the spare mounting hole 33 is aligned with the position where the guide groove 17 and the cam groove 18 overlap, and the three removed cam followers 21 are spared. The cam follower mounting boss 31 provided with the hole 33 is attached. The variable magnification lens 19 is heat crimped to the lens moving frame 20, and discarding the lens moving frame 20 is wasteful because it also discards the expensive variable magnification lens 19, but without such waste. Follow up installation mistakes.

The embodiment has been described in the example provided at a position to divide the outer periphery of the lenses frame at equal intervals, it may not necessarily equally spaced.

  In the embodiment, three preliminary attachment holes 33 are formed at positions rotated by 60 ° in the same direction from a set of three attachment holes 32 provided on the outer peripheral surface 20 a of the lens moving frame 20. However, the spare mounting hole 33 is not limited to this, and may be provided as long as it is provided at a rotationally symmetric position rotated by the same angle from the mounting hole 32. The spare mounting holes 33 are not limited to one set, and may be two sets or three sets.

  In the above embodiment, the cam follower 21 includes the guide roller 22, the cam roller 23, and the tapping screw 24. However, the configuration of the cam follower 21 is not limited thereto. For example, the tapping screw 24 includes a screw member and a sleeve. The sleeve may be fixed to the lens moving frame by a member, and the guide roller 22 and the cam roller 23 may be rotatably supported by the sleeve. Alternatively, a method of fitting the shaft portion 24 a into the guide groove 17 and the cam groove 18 without providing any one or both of the guide roller 22 and the cam roller 23 may be used. Further, instead of the tapping screw 24, a method using a shaft in which the screw portion 24c is a press-fit pin may be used.

  In the above embodiment, the cam follower 21 is inserted through the place where the guide groove 17 formed in the fixed cylinder 12 and the cam groove 18 formed in the cam cylinder 14 overlap. You may make it provide the cam groove for a movement separately.

  In the above embodiment, the cam cylinder 14 is arranged inside the fixed cylinder 12, but there is no problem in adopting the present invention even if the cam cylinder 14 is arranged outside the fixed cylinder 12. The driving device for rotating the cam cylinder 14 may be an apparatus in which an operating member is provided on the casing 41 and the cam cylinder 14 is rotated manually, or a motor is built in and the cam cylinder 14 is rotated by an electric mechanism. As long as the cam cylinder 14 can be rotated, any method may be used.

  In the above-described embodiment, the lens moving frame according to the present invention has been described as being used in the zoom lens apparatus for the zoom lens. However, the present invention is not limited to the zoom lens moving frame, and the focus lens moving frame may be used. It can be adopted.

It is a general-view figure of the zoom lens apparatus provided with the lens moving frame by this invention. It is a perspective view of the lens moving frame which attached the cam follower. FIG. 3 is a partial cross-sectional view of FIG. 2. It is a perspective view of a lens moving frame. It is a perspective view of a projector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Zoom lens apparatus 12 Fixed cylinder 14 Cam cylinder 16 Optical axis 17 Guide groove (straight guide groove)
18 Cam groove (Rotating cam groove)
19 Variable-power lens (second, third, fourth lens group) (Claim of Claim)
20 Lens moving frame 20a Outer peripheral surface 21 Cam follower 22 Guide roller 23 Cam roller 24 Tapping screw (shaft member)
24a Shaft portion 24b Crimp surface 24c Screw portion 31 Cam follower mounting boss 32 Mounting hole 33 Spare mounting hole 34 Receiving surface 40 Projector

Claims (6)

Three cam followers respectively engaging the cam groove formed in the cam barrel holds the lens is attached to the outer peripheral surface, the lens moving frame is moved in the optical axis direction by rotation of the cam barrel,
A set of three attachment holes used when attaching the three cam followers to the outer peripheral surface ;
One set of three or more spare mounting holes, which are provided shifted from the mounting hole in the outer peripheral direction and have the same shape and the same hole spacing as the mounting holes;
Lens movement frame, characterized in that it comprises a. The lens moving frame according to claim 1, wherein the set of three attachment holes is provided at a position where the outer periphery is equally divided for each set.   The cam follower includes a shaft member that is assembled in the mounting hole so as to be perpendicular to the optical axis of the lens, and a cam roller that is rotatably supported by the shaft member and engages with the cam groove. The lens moving frame according to claim 1 or 2.   A fixed cylinder provided coaxially with the cam cylinder is provided with N straight guide grooves extending in parallel with the optical axis, and guide rollers engaging with the straight guide grooves are rotatably supported by the respective shaft members. The lens moving frame according to claim 1, wherein the lens moving frame is provided. The lens moving frame according to any one of claims 3 to 4 , wherein the shaft member is a tapping screw that is screwed into the lens moving frame with the mounting hole as a guide. A receiving surface parallel to the optical axis is formed on the outer peripheral surface so as to surround the periphery of the mounting hole, and the tapping screw is provided on the receiving surface when the tapping screw is screwed into the mounting hole perpendicularly to the optical axis. The lens moving frame according to claim 5, wherein a pressure-bonding surface to be pressure-bonded is formed.

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