JP2006078827A - Lens barrel and lens barrel assembly method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately adjust the eccentricity of a lens in the case of the assembly of a 1st lens frame having a 1st lens group and a 2nd lens frame having a 2nd lens group. <P>SOLUTION: The lens barrel has the 1st lens frame 1 including a 1st barrel part and holding the 1st lens group and the 2nd lens frame 2 including a 2nd barrel part and holding the 2nd lens group, wherein the 1st barrel part has a pawl part 1b projecting in a direction where it is separated from an optical axis, and the 2nd lens frame 2 has a peripheral hole 2c larger than the outside diameter of the pawl part 1b and engaged with the pawl part 1b. The 2nd barrel part is arranged nearer to the 1st lens frame side than the peripheral hole 2c and has a part having an inside diameter larger than the outside diameter of the pawl part 1b and a part having an inside diameter smaller than the outside diameter of the pawl part 1b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens barrel formed by assembling two lens groups and a method for assembling the lens barrel.

  In recent years, due to the compactness of optical elements such as camera lenses and the diversification of aspherical lenses, the amount of eccentricity allowed for a single lens has become strict, and it is necessary to guarantee the optical axis within several μm. This optical axis guarantee is impossible only with the processing accuracy of the lens and ball frame. Accordingly, parallel decentering adjustment is performed between the lens groups when the lens system is assembled.

  Specifically, those disclosed in Patent Documents 1 to 3 are known. In the apparatus of Patent Document 1, a holding member is provided by providing appropriate backs on the lens outer diameter and the inner peripheral surface of the lens holding member. Using a plurality of adjustment screws from the outer periphery of the lens, the inner peripheral surface is brought into contact with the outer diameter portion of the lens to adjust the eccentricity of the plurality of lenses.

  In the apparatus of Patent Document 2, the correction amount of the alignment is obtained by performing image processing on the imaging performance using parallel light transmitted through the first and second lens systems, and one lens system is directly connected. The adjustment jig is adjusted by the correction amount and bonded.

  Furthermore, the apparatus of Patent Document 3 has first and second lens holding members that hold the lens, respectively, and has contact surfaces that contact each other in the optical axis direction, and is provided on one of these contact surfaces. The recessed portion is filled with an adhesive to hold after optical adjustment.

Japanese Utility Model Publication No. 5-36410 JP-A-6-265766 JP-A-8-327869

  However, in the above-described prior art, the adjustment screw method of Patent Document 1 has a structure in which the lens is directly pressed, and therefore, the adjustment may cause a tilt on the opposite surface of the lens barrel surface. Further, since the presser ring is loosened during lens adjustment and tightened after the adjustment, there is a high possibility that the lens will move when the presser ring is tightened.

  On the other hand, as described in Patent Document 2, the correction amount of the alignment is obtained by performing image processing on the imaging performance using parallel light transmitted through the first and second lens systems. The method of directly adjusting and bonding the system with the adjustment jig by the correction amount is possible only when the lens to be adjusted can be moved directly with the adjustment jig, and the lens system is composed of multiple lenses. If it is, adjustment is difficult.

  Further, in the method of Patent Document 3, since the fixing between the holding members after adjustment depends only on the adhesive force of the adhesive, the adhesive is peeled off particularly when a strong force such as an impact is applied to the lens barrel. May occur, the adhesive strength may change due to temperature change / humidity change, and the adjustment accuracy between the lens holding members may be distorted, or in the worst case, the lens holding member may fall off.

  An object of the present invention is to solve the above-mentioned problems and to perform decentration adjustment between the first lens group and the second lens group, which need to be adjusted with respect to each other with high accuracy, and to hold the lens with certainty. An object of the present invention is to provide a lens barrel and a method for assembling the lens barrel.

  Technical features of the lens barrel according to the present invention for achieving the above object include a first lens barrel that includes a first cylindrical portion and holds a first lens group, and a second lens group that includes a second cylindrical portion. A first lens barrel having a claw portion protruding in a direction away from the optical axis, and the second lens barrel is disposed outside the claw portion. A circumferential groove portion that is larger than the diameter and engages with the claw portion, the second tube portion is disposed closer to the first lens barrel than the circumferential groove portion, and the second tube portion is a portion of the claw portion. There exists a part which has an inner diameter larger than an outer diameter, and a part which has an inner diameter smaller than the outer diameter of the said nail | claw part.

  Further, the technical feature of the lens barrel assembling method according to the present invention is that the first lens barrel including the first cylindrical portion and holding the first lens group, and the second lens portion including the second cylindrical portion and holding the second lens group. A first lens barrel having a claw protruding in a direction away from the optical axis, and the second lens barrel has an outer diameter of the claw A circumferential groove portion that engages with the claw portion, the second cylinder portion is disposed closer to the first lens frame than the circumferential groove portion, and the second cylinder portion has an outer diameter of the claw portion. And having a portion having a larger inner diameter and a portion having an inner diameter smaller than the outer diameter of the claw portion.

  According to the lens barrel and the method of assembling the lens barrel according to the present invention, a simple configuration and assembly for adjusting the optical axes of the two lens groups can be realized.

  The present invention will be described in detail based on the embodiments shown in the drawings. A description of the configuration of a general lens barrel will be omitted, and the relationship between some lenses necessary for the description of the present invention and its holding barrel will be described.

  Although the lens barrel in this embodiment holds only the lens, there is no problem even if it holds an optical element other than a refractive optical element such as a diffraction grating or a mirror. Furthermore, it is not limited to an optical element, but may be a holding member that holds a plurality of members that need to be aligned.

  FIG. 1 shows a perspective view of the first lens barrel 1, FIG. 2 shows a perspective view of the second lens barrel 2, and FIG. 3 shows a state in which the first lens barrel 1 is fitted and assembled in the second lens barrel 2. FIG.

  The first lens barrel 1 that holds the first lens group L1 is a substantially bowl-shaped body made of a synthetic resin material, and the second lens barrel 2 that holds the second lens group L2 is also made of a synthetic resin material. The first lens unit L1 and the second lens unit L2 are disposed in the inner part of the inner side of the second lens barrel. The first lens barrel 1 is housed on the front side of the second lens barrel 2, and the peripheral edge of the first lens barrel 1 is joined to the front peripheral edge of the second lens barrel 2. . The lens group may be composed of a single lens or a plurality of lenses, and may include a diffractive optical element or the like.

  A peripheral portion of the first lens barrel 1 is provided with a contact portion 1a facing the rear second lens barrel 2 as shown in the sectional view of FIG. 4, and a cylindrical shape behind the contact portion 1a. For example, three protruding claw portions 1b protrude outwardly at intervals of, for example, 100 ° to 130 °, preferably at intervals of 120 °. An adjustment base 1c protrudes outward from a part of the outer peripheral edge, and a through hole 1d penetrating in the optical axis direction is formed in the adjustment base 1c.

  On the other hand, a contact portion 2 a that faces the front first lens frame 1 side and is joined to the contact portion 1 a of the first lens frame 1 is provided at the front peripheral edge of the second lens frame 2. . Three introduction grooves 2b for introducing the claw portions 1b of the first lens barrel 1 are formed at, for example, three locations on the inner periphery of the contact portion 2a, and the introduction grooves are formed behind these introduction grooves 2b. Circumferential holes 2c that are in communication with 2b and into which the claw portions 1b are fitted are respectively provided.

  These peripheral holes 2c are larger than the outer shape of the claw portion 1b. In particular, the circumferential length around the optical axis is larger than the circumferential width of the introduction groove 2b, and further, the circumferential width of the claw portion 1b. It is big enough. The introduction groove 2b may be a hole penetrating in the radial direction, and the inner diameter of the portion other than the introduction groove 2b at the same position as the introduction groove 2b in the optical axis direction is larger than the outer diameter of the claw portion 1b. Is formed to be smaller.

  Further, in this embodiment, the peripheral hole 2c is a hole penetrating in the radial direction of the center of the optical axis. However, the peripheral hole 2c is not necessarily a complete through hole, and is a substantially cylindrical groove portion centered on the optical axis, or Even the groove portion having a part of the substantially cylindrical shape has no problem. In that case, since it is difficult to inject the adhesive from the outside of the second lens barrel 2 at the time of adhesion, which will be described later, it is preferable to provide a minute hole to the extent that the adhesive can be injected into the groove.

  An adjustment base 2d protrudes outward from a part of the outer peripheral edge of the second lens frame 2 so as to face the adjustment base 1c of the first lens frame 1, and a hole 2e is formed in the optical axis direction. Yes. The hole 2e may be a dead-end hole or a through hole, but its diameter is smaller than the through hole 1d of the first lens barrel 1. Further, a zoom lens moving guide 2 f is formed inside the second lens barrel 2, but the guide 2 f may be a guide portion that penetrates the second lens barrel 2.

  As described above, the first lens barrel 1 is housed in the second lens barrel 2, and the optical axis of the outer diameter portion on the back side of the contact portion 1 a of the first lens barrel 1. The height from O is set to be smaller than the height from the optical axis O of the inner diameter portion of the second lens barrel 2 at the same position, and the gap in the radial direction is set to H. The height of the outer periphery of the claw portion 1b from the optical axis O is often smaller than the height of the introduction groove 2b from the optical axis O, and the gap is larger than the height of the inner diameter portion of the second lens frame 2 from the optical axis O. It is larger than H, preferably at least twice the gap H.

  The center position of the through hole 1d and the hole portion 2e is the same in the height from the optical axis O and the angular phase around the optical axis, but as described above, the inner diameter of the through hole 1d is larger than the inner diameter of the hole portion 2e. The difference between these radii is set to H / 2 to 2H, preferably 0.8H to 1.25H.

  When the first lens barrel 1 and the second lens barrel 2 are assembled, the claw portion 1b of the first lens barrel 1 is inserted into the introduction groove 2b of the second lens barrel 2, and the contact portions 1a, 2a are connected to each other. When the first lens barrel 1 is moved in the rotational direction around the optical axis with respect to the second lens barrel 2 in the state of abutting, the claw portion 1b engages with the peripheral hole 2c, and the first lens barrel is moved. It is possible to prevent the first lens barrel 2 from being detached in the optical axis direction. At this time, the adjustment bases 1c and 2d are substantially matched with each other, and the adjustment pin 3 is press-fitted into the hole 2e through the through hole 1d as shown by a one-dot chain line in FIG. Note that the outer diameter of the adjustment pin 3 is loose with respect to the through hole 1d and is set to a diameter that fits into the hole 2e.

  In this state, with the abutting portions 1a and 2a being in contact with each other, the optical axis is adjusted in a plane orthogonal to the optical axes of the first and second lens groups L1 and L2 using the optical device, and the first, Adjustment is performed so that the optical axes O of the second lens units L1 and L2 coincide with each other. Alternatively, while observing the optical characteristics of the entire optical system including the first lens group L1 and the second lens group L2, adjustment is performed so as to give an eccentric amount so that the characteristics of the entire optical system become the desired optical characteristics. May be. That is, the first lens barrel 1 is decentered in the direction orthogonal to the optical axis O with respect to the second lens barrel 2 within the restriction range by the adjustment pin 3.

  When the eccentricity adjustment is completed and the positional relationship between the first lens frame 1 and the second lens frame 2 is determined, the claw portion 1b and the peripheral hole 2c from the outer diameter side of the second lens frame 2 are determined. An adhesive is injected between them to fix the positional relationship between the first and second lens barrels 1 and 2.

  The position where the adhesive is inserted is not limited to the above-described position, but it is desirable that the adhesive can be easily poured and cured from the outside in consideration of workability of bonding. As another adhesive injection location, it is conceivable to inject a part of the abutting portions 1a and 2a into a gap formed by a notch. Of course, the first lens frame and the second lens frame can be fixed by a method other than bonding.

  Since the adjustment pin 3 is unnecessary after bonding, there is no problem even if it is removed. However, if the bonding is peeled off, the relationship between the first and second lens barrels 1 and 2 may fall within the eccentricity adjustment range, or In order to be effective as a drop-off preventing means, it is desirable to leave it for a predetermined time, preferably until the adhesive is cured.

  As described above, the lens barrel of the present embodiment includes the first lens barrel 1 that includes the first cylindrical portion and holds the first lens unit L1, and the second lens unit that includes the second cylindrical portion and holds the second lens unit L2. The lens barrel 2, the first tube portion has a claw portion 1 b protruding in a direction away from the optical axis, and the second lens barrel 2 has an outer diameter of the claw portion 1 b, that is, three claws. It has a circumferential groove part that is larger than the diameter of the circle when the tip of the part 1b is connected with a circle and engages with the claw part 1b, and the second cylindrical part is closer to the first lens barrel 1 side than the circumferential groove part The introduction groove 2b in which the second cylinder portion has an inner diameter larger than the outer diameter of the claw portion 1b and a portion having an inner diameter smaller than the outer diameter of the claw portion 1b, the same as the introduction groove 2b in the optical axis direction Since the portion other than the introduction groove 2b, that is, the groove is not provided at the position, it has a portion having an inner diameter smaller than that of the introduction groove 2b.

  Here, the circumferential groove portion may be a groove provided inside the second lens barrel 2 or may be a circumferential hole 2c penetrating the second lens barrel 2 in the radial direction. Considering good assembly work efficiency of the lens barrels 1 and 2, it is desirable that the holes be penetrated in the radial direction. Here, in the case of a hole penetrating in the radial direction, that is, in the case of providing the peripheral hole 2c as in the present embodiment, considering the strength of the second lens barrel 2, around the optical axis of the three peripheral groove portions The total occupied angle is preferably 60 ° or less, more preferably 45 ° or less.

  The depth of the introduction groove 2b described above is determined in the radial direction of the second lens barrel 2 at a portion other than the introduction groove 2b at the same position as the introduction groove 2b in the optical axis direction in consideration of the strength of the second lens barrel 2. It is desirable that it is not more than half of the thickness, more preferably not more than 30%.

  Since it is desirable that the position of the first lens frame 1 and the position of the second lens frame 2 are fixed in the optical axis direction, the first lens frame 1 and the second lens frame 2 are There are contact portions 1a and 2a for fixing the positions in the optical axis direction to each other. The positions of these contact portions 1a and 2a are any positions of the first lens frame 1 and the second lens frame 2. As shown in the drawings of the present embodiment, it is not always necessary to provide the first lens barrel 1 at the portion having the largest outer diameter and the end portion of the second lens barrel 2 in the optical axis direction.

  In the present embodiment, the contact portions 1a and 2a are described as being in surface contact with each other, but this is not a limitation, and one of the contact portions 1a and 2a is in contact with the other contact portion at a point. There is no problem. Further, in the present embodiment, the contact portions 1a and 2a are described so as to be in surface contact with each other in a plane perpendicular to the optical axis, but a plane slightly inclined with respect to the plane perpendicular to the optical axis, for example, preferably within 5 degrees. Can also be brought into contact with each other.

  The present embodiment is not limited to the lens barrel described above, and can be used as an interchangeable lens for an imaging apparatus such as a camera including a film camera or a digital camera or a video camera as a single lens barrel. It may be an imaging device such as a camera having a lens barrel or a video camera, and may of course be a binocular or an astronomical telescope. When using for a camera, video camera, etc. or as an interchangeable lens, exchange information such as focus information and zoom information between this lens barrel and the camera body, and the drive lens in the lens barrel It is desirable to be configured to drive.

  According to the present embodiment as described above, it is possible to realize a simple configuration / assembly property and fixing method for adjusting the optical axes of the two lens groups, as well as external forces such as impact and dropping, The lens group can be prevented from falling off even when the adhesive is peeled off due to differences in expansion and contraction due to temperature changes, deterioration of the adhesive itself, etc., and a plurality of claws for loads in the direction of the optical axis due to external forces such as impact and dropping Since the load receives the load, it is possible to obtain an effect that it is difficult to come off and the adhesion is difficult to peel off.

  This lens barrel is useful not only for photographing devices such as single-lens reflex cameras, video cameras, and digital cameras, but also for optical devices such as observation devices such as binoculars and astronomical telescopes.

It is a perspective view of the 1st lens barrel. It is a perspective view of the 2nd lens barrel. It is a perspective view of the state which combined the 1st and 2nd lens frame. It is sectional drawing of the state which combined the 1st and 2nd lens frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st lens frame 1a Contact part 1b Claw part 1c Adjustment base 1d Through-hole 2 2nd lens frame 2a Contact part 2b Introduction groove 2c Peripheral hole 2d Adjustment base 2e Hole 3 Adjustment pin L1 1st lens group L2 Second lens group

Claims (9)

  A lens barrel having a first lens barrel that includes a first barrel and holds a first lens group, and a second lens barrel that holds a second lens group and includes a second barrel, The first cylindrical portion has a claw portion protruding in a direction away from the optical axis, the second lens barrel has a circumferential groove portion that is larger than the outer diameter of the claw portion and engages with the claw portion, Two cylindrical portions are arranged closer to the first lens barrel than the circumferential groove portion, and the second cylindrical portion has a portion having an inner diameter larger than the outer diameter of the claw portion and an inner diameter smaller than the outer diameter of the claw portion. A lens barrel having a portion having   The first contact part of the first lens frame and the second contact part of the second lens frame are parallel to the optical axis of the first lens frame and the second lens frame. 2. The lens barrel according to claim 1, wherein the lens barrel is in contact with each other so as to substantially fix a relative position in any direction.   The lens barrel according to claim 2, wherein the claw portion is disposed closer to the second lens barrel than the first contact portion.   The lens barrel according to any one of claims 1 to 3, wherein the claw portion and the circumferential groove portion are joined with an adhesive.   The first lens barrel has a first adjustment base protruding outward, and the first adjustment base is provided with a through-hole penetrating in the optical axis direction. 5. A second adjustment base corresponding to one adjustment base, wherein the second adjustment base is provided with a hole having a smaller diameter than the through hole in the optical axis direction. The lens barrel according to claim 1.   By fitting an adjustment pin into the hole of the second lens frame through the through hole of the first lens frame, the optical axis of the first lens frame is perpendicular to the optical axis of the first lens frame. 6. The lens barrel according to claim 5, wherein movement within a plane to be controlled is restricted.   An imaging apparatus comprising the lens barrel according to any one of claims 1 to 6 and guiding a light beam through the first lens group and the second lens group to an imaging surface. .   A lens barrel having a first lens barrel that includes a first barrel and holds a first lens group, and a second lens barrel that holds a second lens group and includes a second barrel, The first cylindrical portion has a claw portion protruding in a direction away from the optical axis, the second lens barrel has a circumferential groove portion that is larger than the outer diameter of the claw portion and engages with the claw portion, Two cylindrical portions are arranged closer to the first lens barrel than the circumferential groove portion, and the second cylindrical portion has a portion having an inner diameter larger than the outer diameter of the claw portion and an inner diameter smaller than the outer diameter of the claw portion. A method of assembling the lens barrel.   In the adjustment step, a first adjustment base provided with a through hole protruding outward from the first lens barrel and penetrating in the optical axis direction; and projecting outward from the second lens barrel and penetrating in the optical axis direction A second adjustment base having a hole having a smaller diameter than the hole is opposed to each other, an adjustment pin is inserted into the through hole and the hole, and the first lens frame with respect to the second lens frame 9. The method of assembling a lens barrel according to claim 8, wherein optical adjustment is performed within a range in which a movement amount in a plane with respect to the optical axis is regulated by a gap between the through hole and the adjustment pin.

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