JP2009042531A - Lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel capable of maintaining secure moisture-proof performance and also preventing intrusion of dust or the like. <P>SOLUTION: Between the first lens L1 and second lens L2 held by the first lens holding frame 8 and second lens holding frame 10 respectively, an annular elastic member 11 guided by the lens faces is set. When the lenses are fitted together, the annular elastic member 11 is elastically deformed in the direction of an optical axis, thereby sealing a space between the first and second lenses L1 and L2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lens barrel having a moisture-proof function and an optical adjustment function.

  In the conventional lens barrel, condensation may occur on the front lens that is in direct contact with the external space where the environment such as temperature and humidity changes rapidly. In this case, water droplets can be removed by wiping or evaporating the outer surface of the lens. However, when condensation occurs on the inner surface of the lens, the condensed water droplets must be evaporated or decomposed to remove the water droplets and reassembled.

  In order to cope with this, Patent Document 1 discloses a proposal in which a step portion is provided in a lens and a sealing member is provided on a surface orthogonal to the optical axis to seal the space portion.

JP 2005-250348 A

  The lens barrel of Patent Document 1 is effective when a plurality of lenses are assembled in the same lens holding frame. However, a means for sealing between lenses is disclosed even if another lens holding frame is held on the inner diameter for optical adjustment, and there is an opening that passes through the outer space and the inner space and communicates between the lenses. Not. If the opening is provided, the moisture-proof property cannot be maintained, and dust or the like may be mixed.

  An object of the present invention is to provide a lens barrel that solves the above-described problems and maintains a certain moisture-proof performance by sealing between the lenses, and at the same time, prevents dust and the like from being mixed.

  The technical feature of the lens barrel according to the present invention for achieving the above object is that a first lens holding frame having a first lens and an opening that holds the first lens and penetrates from an outer diameter portion to an inner diameter portion. A second lens juxtaposed with the first lens in the optical axis direction, a second lens holding frame that holds the second lens and is positioned inside the first lens holding frame, the first lens, and the first lens And an annular elastic member that seals the space between the two lenses and inserts an adjustment member into the opening of the first lens holding frame to operate the first lens holding frame. The positional relationship with the second lens holding frame is adjusted, and optical adjustment between the first lens and the second lens is performed.

  According to the lens barrel of the present invention, it is possible to maintain a reliable moisture-proof performance by sealing between the first lens and the second lens, and to have an optical adjustment function, thereby preventing dust and the like from being mixed. .

  The present invention will be described in detail based on the embodiments shown in the drawings.

  FIG. 1 is a longitudinal sectional view of the first embodiment. An interchangeable lens 1 that can be used for a single-lens reflex camera and a digital single-lens reflex camera is a camera system that can be interchanged with a camera body 3 via a mount 2 in the optical axis direction. ing. The photographic lens is composed of a fixed lens group consisting of a first lens L1, a second lens L2, and a third lens L3 arranged in parallel in the optical axis direction, and a movable lens group consisting of a fourth lens L4 and a fifth lens L5. ing.

  A guide cylinder 5 is fixed to the mount 2 via a fixed cylinder 4. The guide cylinder 5 is provided with a linear guide groove for movement (not shown) of the movable lens group. The cam cylinder 6 is disposed on the outer diameter side of the guide cylinder 5, and the three bayonet claws 5 a formed on the outer diameter side engage with the circumferential groove 6 a of the cam cylinder 6 in the optical axis direction of the cam cylinder 6. While restricting the movement, the cam cylinder 6 is rotated at a fixed position during the focus adjustment. Further, the cam cylinder 6 is provided with a moving cam groove 6b for the movable lens group.

  The first lens holding frame 8 is in contact with the guide tube 5 by a plane orthogonal to the optical axis direction and is fixed by screws (not shown), and holds the first lens L1 and the third lens L3. The first lens L1 is pressed from the front by the lens presser 9. A second lens holding frame 10 that holds the second lens L <b> 2 is disposed inside the first lens holding frame 8.

  Between the first lens L1 and the second lens L2, a semi-closed cell type annular elastic member 11 made of, for example, elastic rubber is incorporated with a surface parallel to the optical axis of the second lens L2 as a guide.

  The fourth lens L4 is held by the fourth lens holding frame 12, the lens pressing ring 13 presses the fourth lens L4, and the screw portion 13a is screwed to the fourth lens holding frame 12. A cylindrical cam follower (not shown) is attached to the fourth lens holding frame 12 at three positions on the outer diameter side, and the fourth lens holding frame 12 is driven along the cam locus of the cam barrel 6 and is driven by the fourth lens L4. A focusing operation is performed. The fifth lens L5 is held by the fifth lens holding frame 14.

  A focus unit 15 incorporating an ultrasonic motor is arranged on the subject side of the fixed cylinder 4, and the focus unit 15 is provided with a differential mechanism. A manual operation ring 16 is disposed outside the lens barrel between the fixed cylinder 4 and the guide cylinder 5. Automatic focusing operation by rotating the manual operation ring 16 and the rotation of the rotor of the ultrasonic motor of the focus unit 15 by rotating the cam cylinder 6 through a guide key 17 fixed to the cam cylinder 6 from a focus key (not shown). Is made.

  An annular main substrate (not shown) that constitutes an electric circuit inside the interchangeable lens 1 is incorporated in a fixed cylinder 4 in the vicinity of the mount 2. The main board performs focusing control in the interchangeable lens 1 and control of a diaphragm (not shown) while receiving communication with the camera body 3 and power supply through a contact block (not shown).

  FIG. 2 is a perspective view of a disassembled state of main parts related to the parallel eccentricity adjusting mechanism of the embodiment. The main components are a first lens holding frame 8 holding the lens L3, a second lens holding frame 10 holding the second lens L2, an annular elastic member 11, a first light shielding member 18, a first lens L1, and a lens presser. It consists of nine.

  FIG. 3 is a perspective view of the assembled state. Openings 8a penetrating from the outer diameter portion of the first lens holding frame 8 to the inner diameter portion thereof toward the optical axis center are provided at three equiangular positions around the optical axis on the outer periphery of the first lens holding frame 8. It has been. The opening 8a has a square hole shape including a longitudinal groove 8b parallel to the optical axis and a long groove 8c extending in the circumferential direction in a plane orthogonal to the optical axis. In addition, roller seats 10a are provided at three positions on the outer periphery of the second lens holding frame 10 so as to face the opening 8a.

  In a state where the first lens holding frame 8 and the second lens holding frame 10 are combined, as shown in FIG. 4, the adjustment member 20 is inserted into the opening 8 a toward the center of the optical axis, and the second lens is held by the screw 21. The frame 10 is fixed to a roller seat 10a shown in FIG.

  The adjustment member 20 has a head 20a engaged with the longitudinal groove 8b, and the head 20a is eccentric with respect to the eccentric shaft portion 20b. The head portion 20a only needs to be eccentric in at least two of the adjustment members 20 arranged at three locations, and the remaining portion of the head portion 20a is not eccentric with respect to the shaft portion 20b. But there is no problem.

  With such a configuration, the position of the second lens holding frame 10 within the optical axis orthogonal plane is restricted by the adjustment member 20, and the adjustment member 20 can be operated by rotation around the eccentric shaft portion 20b in the opening 8a. It is possible. By rotating the adjusting member 20, the second lens holding frame 10 is controlled in the optical axis orthogonal plane by the interaction between the head 20a and the long groove 8c while the position in the optical axis direction is regulated by the adjusting member 20 and the vertical groove 8b. To adjust the positional relationship with the first lens holding frame 8. At this time, by rotating the adjustment members 20 at two or more locations, the second lens holding frame 10 has no eccentricity adjustment or tilt adjustment according to the eccentricity amounts of the head portion 20a and the shaft portion 20b of the adjustment member 20. Can be changed in stages.

  FIG. 5 is a cross-sectional view of the main part of the first lens holding frame 8 in the present embodiment. The first lens holding frame 8 holds the first lens L1 and the third lens L3. The helical thread 9a of the lens retainer 9 and the outer peripheral spiral thread groove 8d of the first lens holding frame 8 are screwed together, and the first lens L1 is pressed in the optical axis direction by the lens retainer 9. The first lens holding frame 8 is formed with three bayonet claws 8e on the outer diameter side so as to be held by a tool when adjusting the parallel eccentricity between the fixed lens group and the movable lens group.

  Further, a first light shielding member 18 is interposed between the first lens L1 and the annular elastic member 11 for the purpose of blocking harmful light. The second lens L2 is held by the second lens holding frame 10, and the second light shielding member 22 is incorporated between the second lenses L2 and L3 at the same time.

  When the first lens L1 and the first light shielding member 18 are assembled, the annular elastic member 11 is elastically deformed in the optical axis direction from the initial state H1 to the distance H2 between the first light shielding member 18 and the second lens holding frame 10, As a result, the space between the first lens L1 and the second lens L2 is sealed. The annular elastic member 11 is pressed against the abutting surface 5b of the guide tube 5 when the first lens holding frame 8 is assembled, and is formed into a closed cell, thereby improving airtightness with the outside. The annular elastic member 11 may be polyurethane, polyethylene, rubber sponge, polyolefin foam, or silicone rubber.

  Even when the parallel eccentric adjustment or the tilt adjustment is performed by the adjustment member 20, the annular elastic member 11 is brought into contact with the surface L2a provided on the second lens L2 parallel to the optical axis while maintaining the elastic deformation state. Therefore, even if the first lens holding frame 8 is provided with the optical adjustment opening 8a, the sealed state of the space between the first lens L1 and the second lens L2 can be maintained.

  FIG. 6 is an enlarged cross-sectional view of a main part of the second embodiment. In addition, the same code | symbol as Example 1 has shown the same member. In the annular elastic member 23 interposed between the first lens L1 and the second lens L2, an annular flat surface portion 23a orthogonal to the optical axis and a cylindrical portion 23b extending in the optical axis direction are integrally formed. The flat portion 23a is in contact with the body-mounted surface of the first lens L1, and is fixed to the first lens L1 with an adhesive tape or the like. An end portion of the cylindrical portion 23b is in contact with the first guide surface 10b provided on the second lens holding frame 10.

  Here, the flange portion 23c on the inner side of the flat surface portion 23a of the annular elastic member 23 extends to the inner diameter side up to the vicinity of a line segment Y connecting the effective diameter of the first lens L1 and the effective diameter of the second lens L2. . Thereby, since the space part between the 1st lens L1 and the 2nd lens L2 can be sealed, shielding a harmful ray, reliable moisture-proof property can be maintained.

  Even when the optical adjustment is performed by the adjustment member 20 described above, only the cylindrical portion 23b of the annular elastic member 23 is elastically deformed, and the bonded flat portion 23a is not affected by the adjustment. Therefore, even if eccentricity adjustment or tilt adjustment is performed, the line segment Y connecting the effective diameters of the flange portion 23c is not blocked.

That is, regarding the inner diameter dimension of the flange portion 23c of the annular elastic member 23, it is desirable that the following relationship be considered in consideration of the optical adjustment amount. The effective diameter of the rear surface of the first lens L1 is D1, the inner diameter of the flange portion 23c of the annular elastic member 23 is d1, the effective diameter of the front surface of the second lens L2 is D2, and the optical adjustment amount of the second lens L2 is d2. To do.
D1> (d1 + d2)> D2

  In addition, it is desirable that the inner diameter d1 of the flange portion 23c of the annular elastic member 23 is smaller than the surface L2a provided on the second lens L2 and parallel to the optical axis. At that time, the antireflection effect can be enhanced by making the end surface of the flange portion 23c into a satin finish or an edge shape.

  Further, by sandwiching the second annular elastic member 24 between the first lens holding frame 8 and the second lens holding frame 10, the space between the second lenses L2 and L3 can be similarly sealed. it can. Since the second annular elastic member 24 contacts the guide surface 10c extending from the second lens holding frame 10 in parallel with the optical axis, the sealing performance can be maintained while maintaining the elastic state even during the optical adjustment described above. it can.

2 is a longitudinal sectional view of a lens barrel of Embodiment 1. FIG. It is a perspective view of the decomposition | disassembly state of a lens adjustment mechanism. It is a perspective view of the assembly state of a lens adjustment mechanism. It is a perspective view of a lens adjustment member. It is principal part sectional drawing. 10 is an enlarged cross-sectional view of a main part of Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Interchangeable lens 2 Mount 3 Camera body 4 Fixed cylinder 5 Guide cylinder 8 1st lens holding frame 10 2nd lens holding frame 11, 23, 24 Annular elastic member 15 Focus unit 16 Manual operation ring 18, 22 Light-shielding member 20 Adjustment member 20a Head 20b Eccentric shaft L1 First lens L2 Second lens L3 Third lens L4 Fourth lens L5 Fifth lens

Claims (10)

  A first lens, a first lens holding frame that holds the first lens and has an opening that penetrates from the outer diameter portion to the inner diameter portion, a second lens that is parallel to the first lens in the optical axis direction, and the first lens A second lens holding frame that holds two lenses and is located inside the first lens holding frame; and an annular elastic member that is between the first lens and the second lens and seals a space between them. Then, the positional relationship between the first lens holding frame and the second lens holding frame is adjusted by inserting and operating an adjustment member into the opening of the first lens holding frame, and the first lens and the A lens barrel that performs optical adjustment with the second lens.   The lens barrel according to claim 1, wherein the optical adjustment is eccentricity adjustment.   The lens barrel according to claim 1, wherein the optical adjustment is a tilt adjustment.   The lens barrel according to any one of claims 1 to 3, wherein the annular elastic member is made of any one of elastic rubber, polyurethane, polyethylene, rubber sponge, polyolefin foam, and silicone rubber.   The annular elastic member is disposed perpendicular to the optical axis, and a flange portion that contacts the first lens and a cylindrical portion that extends in the optical axis direction and contacts the second lens are integrally formed. The lens barrel according to any one of claims 1 to 4, wherein the lens barrel is characterized by the following.   The annular elastic member is disposed perpendicular to the optical axis, and a flange portion that contacts the first lens and a cylindrical portion that extends in the optical axis direction and contacts the second lens holding frame are integrally formed. The lens barrel according to any one of claims 1 to 5, wherein:   The lens barrel according to claim 5 or 6, wherein an inner diameter dimension of the flange portion of the annular elastic member is between an effective diameter of the first lens and an effective diameter of the second lens. .   The lens barrel according to claim 5 or 6, wherein a satin finish is applied to an inner diameter portion of the flange portion of the annular elastic member.   The lens barrel according to claim 5 or 6, wherein an inner diameter portion of the flange portion of the annular elastic member is formed in an edge shape.   A camera system comprising the lens barrel according to claim 1.

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