JP4129283B2 - Lens barrel - Google Patents

Description

  The present invention relates to a lens barrel, and more particularly to a lens barrel having a light shielding portion that prevents light incident from between the barrels relatively moving in the optical axis direction and / or the rotation direction.

  A camera having a zoom function and a retractable function of a lens has a lens barrel composed of a plurality of barrels such as a lens barrel, a rectilinear barrel, a rotary barrel, and a fixed barrel. In this type of camera, the zoom function and the collapsing function are realized by moving the lens barrels relative to each other and the exterior cover of the camera body in the optical axis direction and / or the rotation direction. .

  In the above lens barrel, in order to reduce the driving load at the time of relative movement of the lens barrel, a slight gap is provided between the lens barrels facing each other and between the exterior cover and the lens barrel of the camera body. If this gap is not sufficiently shielded from light, unnecessary external light may enter the camera body directly or indirectly (secondary reflection or scattering) and reach the film surface to expose the film. Arise.

  Accordingly, various proposals have been made in the past for preventing external light from entering the camera body from the gap. For example, as shown in FIG. 8, a light shielding device for a camera disclosed in Japanese Utility Model Publication No. 5-61711 is an annular synthetic resin sheet having an inner diameter smaller than the outer diameter of a movable cylinder 101 that holds a photographing lens. The light shielding member 103 formed by bonding the member 103a to the annular light shielding sheet base plate 103b is fixed to the front cover 102 of the camera body, and the sheet member 103a is pressed against the movable cylinder 101 and brought into surface contact. In addition, external light is prevented from entering through a gap between the movable cylinder 101 and the front cover 102 of the camera body.

Most conventional light-shielding devices employ the above-described configuration.
Japanese Utility Model Publication No. 5-61711

  By the way, the light shielding device of the camera proposed in Japanese Utility Model Laid-Open No. 5-61711 realizes light shielding by bringing only one elastic light shielding means (the sheet member 103a in the above example) into surface contact with the inner wall surface of the movable cylinder. Mechanism. However, the light shielding device having such a configuration has a problem that surface contact becomes unstable when the movable cylinder is decentered with respect to the optical axis, and complete light shielding performance cannot be obtained.

  On the other hand, in recent years, downsizing of cameras has been increasingly desired, and the influence has spread to the lens barrel. In order to reduce the size of the lens barrel, it is necessary to reduce the size of the light shielding device provided inside.

  However, when the light-shielding device as described above is downsized, there is a possibility that the following problems, in particular, a problem that the light-shielding performance deteriorates may occur.

  First, problems that occur when the elastic light shielding means is downsized in the direction (radial direction) perpendicular to the optical axis will be described.

  First, if the outer diameter of the support member (light-shielding sheet base plate 103b) of the elastic light-shielding means (sheet member 103a) is cut to reduce the size, the attachment strength of the sheet member decreases. As a result, the contact with the movable cylinder 101 becomes unstable, resulting in a problem that a complete light shielding performance cannot be obtained.

  That is, if the outer diameter of the support member is reduced, the rigidity of the support member itself is reduced, and the support member receives a force in the direction of the optical axis due to the relative movement of the lens barrels, causing a conical (disc spring-like) deformation. End up. Thereby, the amount of wrapping of the sheet member is reduced, and there is a problem that light enters.

  Secondly, if the inner diameter is reduced without changing the radial thickness of the support member, and the wrap portion of the sheet member is further cut to reduce the size, the wrap amount becomes smaller depending on the cut amount. In this case, external light tends to leak due to the eccentricity of the lens barrel (movable cylinder).

  Further, the curvature of the bent portion of the sheet member is reduced, and the burden on the lens barrel is increased. That is, even if the sheet member is formed to be thin to some extent, a considerable load is generated at the contact portion between the lens barrel and the sheet member, and the driving load between the lens barrels is increased.

  Next, problems that occur when the elastic light shielding means is downsized in the optical axis direction will be described.

  First, when the wrap amount in the optical axis direction in which the sheet member 103a is in contact with the movable tube 101 is reduced, external light is likely to leak due to eccentricity of the lens barrel as described above. In addition, the curvature of the bent portion of the sheet member is reduced, and there is a problem that the burden on the lens barrel increases as described above.

  Second, if the sheet member is reduced in thickness by reducing the sheet thickness, the light shielding property of the sheet member itself is lowered. In other words, when the sheet thickness of the sheet member is thin, external light is transmitted when it directly strikes the sheet member. In addition, since the light beam is scattered when passing through the sheet member, the light beam that has entered the camera causes the film surface to be exposed over a wide range.

  Thirdly, if the size of the sheet member is reduced by reducing the thickness of the support member, the rigidity is lowered. As a result, the contact with the movable cylinder becomes unstable, and there arises a problem that the complete light shielding performance cannot be obtained as described above.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a lens barrel of a camera that can reliably block external light even if the barrel is decentered with respect to the optical axis.

In order to achieve the above object, a lens barrel according to an aspect of the present invention includes a first lens barrel having a first notch step for arranging a light shielding member,
Forming a space together with the first notch step portion, a second lens barrel rotating with respect to the first lens barrel; and
A third barrel that moves in the optical axis direction relative to the first barrel in conjunction with the rotational movement of the second barrel;
A first light-shielding member having a ring-shaped inward flange having an inner diameter slightly larger than the outer diameter of the third lens barrel, protruding from the inner peripheral surface of the distal end portion of the second lens barrel;
A ring-shaped support having a rotation stop projection for engaging with the groove of the first lens barrel, and an outer peripheral surface of the third lens barrel provided integrally with the support and elastically deforming. A second light shielding member disposed in a space formed by the second lens barrel and the first cut-in step portion,
Comprising
The support that forms the second light shielding member is engaged with the groove portion of the first lens barrel so as not to rotate more than a predetermined amount with respect to the first lens barrel, and further, the third mirror When the tube moves in the optical axis direction with respect to the first lens barrel, the third lens barrel is disposed so as to be relatively movable in the optical axis direction,
The light shielding sheet has the ring-shaped inward flange when the support is moved in the optical axis direction and the radial direction by the third lens barrel being eccentric with respect to the optical axis. Light rays entering the camera body are shielded from a gap between the light shielding member and the outer peripheral surface of the third lens barrel.

  The lens barrel of the camera according to the present invention has an effect of reliably blocking external light even if the barrel is decentered with respect to the optical axis.

The present invention will be described below with reference to the illustrated embodiments.
1 to 4 relate to a first embodiment of the present invention, and FIG. 1 is a central longitudinal sectional view of a camera having a lens barrel according to the present invention.

  In this embodiment, the present invention is applied to a retractable zoom lens barrel, and the lens barrel 1 advances and retracts between a retracted position which is a storage position with respect to the camera body and a projecting projecting position. A movable cylinder and a fixed cylinder are included.

  The camera body 200 having the lens barrel 1 includes a camera body (not shown), an exterior cover 15 that covers the camera body, and a back cover 20, and main parts thereof are configured. A film rail 15b for positioning in the axial direction is formed, and a pressure plate 21 for pressing the film is attached to the back cover 20. The lens barrel 1 is disposed on the front surface of the camera body 200 so as to protrude from the opening 15a formed on the front surface of the exterior cover 15 so as to face the film 201 positioned at the photographing position. ing.

  The lens barrel 1 includes a rotating cylinder 3 as a zooming outer frame that is fitted in a retractable fixed cylinder 2 and is rotatable with respect to the fixed cylinder 2, and a fixed cylinder in accordance with the rotation of the rotating cylinder 3. A cam cylinder 4 that is driven forward and backward by the cam 2, a rectilinear cylinder 5 that is rotatably fitted to the cam cylinder 4, is guided by the fixed cylinder 2, and is driven forward and backward simultaneously with the cam cylinder 4, A lens holding cylinder 6 that is fitted to the cylinder 4 and whose rotation is limited to the linear cylinder 5 and is driven forward and backward by the cam of the cam cylinder 4 is supported by the lens holding cylinder 6 so as to be able to advance and retract. A first lens frame 7 that holds a certain first group lens 7a, a shutter 9 that moves forward and backward integrally with the lens holding cylinder 6, and a second group lens that is driven forward and backward by a cam of the cam cylinder 4 and is a zoom lens. And a second lens frame 8 that holds 8a.

  An outward flange is formed at the base end portion of the fixed cylinder 2, and a female screw 2c is screwed to the flange. A screw shaft 12 with a male screw cut is engaged with the female screw 2c, and when the screw shaft 12 is rotated by a driving force from a driving unit (not shown) provided in the camera body, the fixed cylinder 2 is retracted or protruded. It is designed to move forward and backward.

  The rotating cylinder 3 is rotatably fitted on the outer peripheral surface of the fixed cylinder 2. A circumferential groove 3d is provided on the inner peripheral surface of the distal end portion of the rotating cylinder 3, and a flange 2g formed on the outer periphery of the distal end of the fixed cylinder 2 is fitted into the circumferential groove 3d, so that the rotation The relative movement of the cylinder 3 in the optical axis direction with respect to the fixed cylinder 2 is restricted. Further, a driving gear 3 b is formed on the outer peripheral surface of the rotating cylinder 3 on the base end side, and this gear 3 b is meshed with a pinion gear 11 a fixed to one end side of the zoom driving shaft 11. . A transmission gear 11b fixed to the other end of the zoom drive shaft 11 is engaged with a gear of a zoom drive unit (not shown) provided on the camera body.

  Further, a rectilinear guide pin 5a is formed on the outer peripheral surface of the base end side of the rectilinear cylinder 5 fitted to the inner peripheral surface of the fixed cylinder 2, and the pin 5a is formed on the fixed cylinder 2 with the pin 5a. Is fitted in a rectilinear groove 2b formed in the optical axis direction on the inner surface, and the rectilinear cylinder 5 is restricted so as to be movable only in the optical axis direction.

  The cam cylinder 4 is rotatably fitted inside the linear cylinder 5. A circumferential groove 4d is provided on the outer peripheral surface of the base end side of the cam cylinder 4, and an inward protrusion 5c formed on the base end side of the rectilinear cylinder 5 is fitted into the peripheral groove 4d. The relative movement of the cam cylinder 4 in the optical axis direction with respect to the linear cylinder 5 is restricted. Further, a zoom pin 4a is formed to project outwardly on the base end side of the cam cylinder 4. The pin 4a includes the inclined cam groove hole 2a formed in the fixed cylinder 2 in a partial arc shape, and the above-described pin 4a. The rotary cylinder 3 is fitted in a rectilinear groove 3a drilled in the optical axis direction on the inner peripheral surface.

  In addition, an inclined cam groove 4b having a partial arc shape is provided on the inner peripheral surface of the cam cylinder 4, and a pin 8b protruding from the second lens frame 8 is fitted into the cam groove 4b.

  The lens holding cylinder 6 is fitted on the outer peripheral surface side of the cam cylinder 4 and on the inner peripheral surface side of the rectilinear cylinder 5. On the base end side of the lens holding cylinder 6, pins 6 b and 6 a projecting inward and outward are formed, and the pin 6 b projecting inward is formed in a partial arc shape on the outer peripheral surface of the cam cylinder 4. A pin 6 a that is fitted into the provided inclined cam groove 4 c and protrudes outward is fitted into a rectilinear groove 5 b provided on the inner peripheral surface of the rectilinear cylinder 5 in the optical axis direction.

  The first lens frame 7 is disposed inside the front end of the lens holding cylinder 6. The lens holding cylinder 6 is provided with a driving mechanism (not shown) for focusing the first lens frame 7 by moving it straight in the optical axis direction. The lens holding cylinder 6 is provided with a shutter 9 behind the first lens frame 7.

  Further, a bellows 14 is provided between the inward flange on the base end side of the fixed cylinder 2 and the rear inner wall of the exterior cover 15, and the light tightness is maintained with respect to the film 201 together with the back cover 20. ing. The bellows 14 expands and contracts as the lens barrel 1 protrudes and retracts.

The operation of the lens barrel 1 thus configured will be briefly described.
First, the screw shaft 12 is rotated by a driving force from a driving unit (not shown), and the lens barrel 1 in the retracted position is extended to the photographing position. Then, after the lens barrel 1 is extended to the photographing position, when a driving force from a zoom drive unit (not shown) is transmitted to the rotary cylinder 3 via the pinion gear 11a, the rotary cylinder 3 rotates. The rotational force of the rotating cylinder 3 is transmitted to the zoom pin 4a fitted in the rectilinear groove 3a. When the zoom pin 4a rotates along the cam groove hole 2a, the cam cylinder 4 is moved relative to the fixed cylinder 2. Then, it moves forward and backward in the optical axis direction while rotating around the optical axis O. At this time, as the cam cylinder 4 moves, the rectilinear cylinder 5 moves forward and backward in the optical axis direction integrally with the cam cylinder 4 without rotating. When the cam cylinder 4 rotates, the rotational force is transmitted to the lens holding cylinder 6 and the second lens frame 8 by the pins 6b and 8b fitted in the cam grooves 4c and 4b. The second lens frame 8 moves forward and backward in the optical axis direction relative to the rectilinear barrel 5 while moving linearly relative to the rectilinear barrel 5 in the optical axis direction. By these operations, the positions of the first group lens 7a and the second group lens 8a are controlled, and the lens barrel 1 operates in a telescopic manner from the tele position to the wide position in the optical axis direction. FIG. 1 shows a state in which the lenses 7a and 8a are set on the long focal side.

  In the lens barrel 1 configured as described above, the inner circumference of the tip of the rotating barrel 3, the inner circumference of the tip of the rectilinear barrel 5, and the opening 15a of the exterior cover 15 are provided in the present invention. The light shielding portions A, B, and C are provided.

Next, the configuration of the light shielding portions A, B, and C will be described in detail with reference to FIGS.
In addition, although the structure of the light-shielding part A among the said light-shielding parts A, B, and C is demonstrated here, the structure of the said light-shielding parts B and C is also the same structure as the said light-shielding part A.

  2 is an enlarged cross-sectional view of the main part of the light-shielding part A provided in the lens barrel of FIG. 1, FIG. 3 is a cross-sectional view taken along the line I-I of FIG. 2, and FIG. FIG. 5 is an explanatory view showing the cross-sectional shape of the lip portion, and FIG. 5A is an enlarged cross-sectional view taken along the line II-II in FIG.

Prior to the description of the configuration of the light shielding portion A, the configurations of the distal end portions of the fixed cylinder 2 and the rotating cylinder 3 will be described in a little more detail.
As shown in FIG. 2, a cut-out step portion 3e for arranging a light shielding member is formed on the front end surface of the rotary cylinder 3 toward the inner peripheral side, and the inner surface of the inward flange 3c formed thereby is formed. Is in contact with the front end surface 2h of the fixed cylinder 2. A notch step 2d for disposing the light shielding ring is formed on the inner peripheral side of the front end surface 2h, and the notch step 2d cuts the inner peripheral side of the flange 3c and the notch opposite thereto. A predetermined gap is formed between the step surface. Further, on the outer peripheral surface side of the distal end flange portion 2e of the fixed cylinder 2, a radial groove 2f into which a rotation stopping projection 32a formed on a light shielding ring described later enters is formed at a symmetrical position (see FIG. 2 and FIG. 2). (See FIG. 3).

The light shielding part A includes a light shielding member 30 and a light shielding ring 31.
As shown in FIGS. 2 to 4 and FIG. 5A, the light shielding ring 31 includes a support 32 and a light shielding sheet 33.

  The support 32 is a donut disk-shaped member made of a metal material having an outer diameter smaller than the outer diameter of the notch step 2d and an inner diameter smaller than the outer diameter of the rectilinear cylinder 5. The pair of rotation stop projections 32a and 32a (see FIG. 4) are integrally formed at the symmetrical position of the outer peripheral surface of the support 32.

  The light shielding sheet 33 is obtained by molding a black silicon rubber annular body on the donut-shaped support body 32. The sheet 33 is a donut disk-shaped member having an outer diameter smaller than the outer diameter of the support 32 and an inner diameter smaller than the outer diameter of the rectilinear cylinder 5. The portion is a lip portion 33 a that is in pressure contact with the outer peripheral surface of the rectilinear cylinder 5. On the inner surface of the light shielding sheet 33, a ring-shaped protrusion 33b that abuts against the inner peripheral surface of the support 32 is formed. The protruding height of the protruding portion 33b is the same as the plate thickness of the support 32.

  The light shielding sheet 33 has its upper half on the inner surface side and the upper surface side of the projecting portion 33b fixed to the support body 32 by molding, and constitutes the light shielding ring 31 together with the support body 32. A portion protruding inward from the body 32, that is, a portion extending inward from the protruding portion 33b of the light shielding sheet 33 is a lip portion 33a. The inner diameter of the lip portion 33a is smaller than the outer diameter of the rectilinear cylinder 5 in a natural state.

  The light shielding ring 31 configured in this manner is in a state in which the rotation stop protrusions 32a and 32a of the support 32 are engaged with the grooves 2f and 2f (only one is shown in FIGS. 2 and 3) of the fixed cylinder 2. Therefore, it is arranged in the cut step 2d for arranging the light shielding ring. In this state, the lip portion 33a is pressed against the outer peripheral surface of the rectilinear cylinder 5 in a state of being elastically deformed and bent. The gap in the optical axis direction of the notch step portion 2d is formed to be approximately the same as the thickness of the light shielding ring 31 or slightly larger than the thickness of the light shielding ring 31, and the rectilinear cylinder 5 is a fixed cylinder. 2, the light-shielding ring 31 and the rectilinear cylinder 5 move relative to each other in the optical axis direction. The support 32 is formed to be movable in a radial direction with respect to the rectilinear cylinder 5 by a predetermined amount. When the rectilinear cylinder 5 is eccentric with respect to the optical axis due to play or the like, the light shielding ring 31 is configured to move integrally with the rectilinear cylinder 5 in the radial direction in a state where the lip portion 33 a is in pressure contact with the outer peripheral surface of the rectilinear cylinder 5. Further, the groove 2f formed at the distal end portion of the fixed cylinder 2 is formed to have a predetermined width in the rotation direction with respect to the rotation stopping projection 32a. Has a predetermined degree of freedom with respect to the rotation direction. The protrusion 32a is engaged with the groove 2f so that the ring 31 does not rotate more than a predetermined amount even when the light shielding ring 31 receives a frictional rotational force from the rotary cylinder 3, and the protrusion 32a is engaged with the protrusion 32a. On the other hand, the groove 2f is wider because the protrusion 32a is pressed against the wall of the groove 2f by the eccentricity of the straight cylinder 5 so that the lip 33a is deformed and the light beam enters the camera from there. It is for preventing.

  As the material for forming the support body 32, phosphor bronze, stainless steel, or the like, which is not easily rusted and has high rigidity, is employed. In addition, an alloy in which iron, copper, aluminum, or the like is mixed at a predetermined ratio may be used.

  The rotation stop protrusions 32a of the support 32 are formed at two positions on the outer periphery in the present embodiment, but the number of the rotation stop protrusions 32a is not limited to this, and is one or more than three. It may be. The rotation stop projection 32a can be used as a connecting portion between the supports when the support 32 is manufactured by pressing or etching and mass-produced. Of course, the light-shielding effect of the present invention can be sufficiently obtained without the projection 32a.

  On the other hand, the light shielding member 30 is disposed immediately before the lip portion 33a. That is, the base is bonded and fixed to the notch step portion 3 e formed on the front end surface of the rotating cylinder 3. The light shielding member 30 is a ring-shaped member having an outer diameter that is substantially the same as the inner diameter of the rotary cylinder 3 and an inner diameter that is smaller than the outer diameter of the rectilinear cylinder 5. As shown in FIG. 2, the cross-sectional shape of the light shielding member 30 includes a rectangular base portion 30a having an adhesive surface on the outer peripheral side, a bent portion 30b extending from the inner peripheral side of the base portion 30a, and the bent portion 30b. It has a shape having a front lip portion 30d extending forward and a rear lip portion 30c extending rearward.

  In the light shielding member 30, the adhesive surface of the base portion 30a is bonded and fixed to the inner peripheral surface of the cut step portion 3e, and the front lip portion 30d and the rear lip portion 30c are outer peripheral surfaces of the rectilinear cylinder 5. Is in pressure contact.

  The material for forming the light shielding member 30 and the light shielding sheet 33 is preferably an elastomer material since the lip portion is required to have a large elastic deformation, and specifically, rubber is optimal. In the present embodiment, silicon rubber or fluorine rubber excellent in temperature and humidity resistance, chemical resistance, and weather resistance is employed.

  Further, in order to prevent the low molecular weight silicone resin and fluororesin contained in the silicon rubber and fluororubber from seeping out and to reduce the sliding load, the lip portion has tetrafluoroethylene (hereinafter referred to as Teflon (registered trademark)). ))) With a resin coating. This resin coating is performed by painting, but since silicon rubber and fluororubber have poor wettability of the resin, the resin coating is performed after applying a primer in advance to improve the adhesion of the resin paint. As another coating method, xylene or the like may be performed by a CVD (Chemical Vapor Deposition) method. Although the coating of xylene by this CVD method has a higher coefficient of friction than the coating of resin containing Teflon (registered trademark), a uniform film can be formed, so that a stable operation of the light shielding ring can be obtained.

The operation and effect of the light shielding part A configured as described above will be described below.
In the light shielding portion A, in a normal state, that is, in a state where the fixed cylinder 2, the rotating cylinder 3, and the rectilinear cylinder 5 are not decentered with respect to the optical axis, external light incident on the camera body is shielded from the light shielding member 30. Is sufficiently shielded from light so that direct light does not enter the camera.

  However, each of the cylinders moves with respect to the optical axis, the rotating cylinder 3 is eccentric with respect to the fixed cylinder 2, or the rectilinear cylinder 5 is eccentric with respect to the fixed cylinder 2. It is assumed that the rear lip portions 30d and 30c are deformed by the amount of eccentricity and a gap is formed between the rearwardly moving cylinder 5 (that is, the front and rear lip portions 30d and 30c are dotted lines in FIG. When the external light enters from the gap, the direct light of the external light enters the back of the light shielding member 30. However, this directly incident light is shielded by the lip portion 33 a of the light shielding ring 31. That is, even when the fixed cylinder is eccentric with respect to the optical axis, the light shielding ring 31 moves together with the rectilinear cylinder 5, so that the lip portion 33 a is in pressure contact with the outer peripheral surface of the rectilinear cylinder 5. The incident light is blocked by the lip portion 33a.

  Here, the incident light that directly reaches the light shielding ring 31 without being shielded by the light shielding member 30 is incident on the outer periphery of the rectilinear cylinder 5 that is parallel to the rectilinear cylinder 5. Light. For this reason, this directly incident light strikes the tip surface of the lip portion 33a of the light shielding ring 31 (see FIG. 2). In this case, the length of the portion of the lip portion 33a pressed against the rectilinear cylinder 5 is the thickness of the lip portion 33a with respect to the incident light. Therefore, even if the light shielding sheet 33 is made thin, And a sufficient thickness. In other words, the thickness of the light shielding sheet 33 can be reduced, and in this embodiment, the minimum thickness of the lip portion 33a of the light shielding sheet 33 can be reduced to 0.1 mm. Incidentally, the lip portion 33a of the light shielding sheet 33 made of silicon rubber mixed with about 5% by weight of a black pigment made of carbon or iron oxide (the characteristic of the silicon rubber is deteriorated when 5% by weight or more of the pigment is mixed) is 0.1 mm. When formed thick, the lip portion 33a transmits some light for direct light, but has sufficient light blocking performance for indirect light such as reflected light. However, as described above, since the length of the lip portion 33a pressed against the outer peripheral surface of the rectilinear cylinder 5 is the thickness for the direct light, the sheet thickness for the direct light can be gained, and the external light is the lip. The light does not pass through the portion 33a and enter the camera body.

  In order to reduce sliding resistance, the surface of the light shielding member 30 and the light shielding sheet 33 is coated with a lubricant in which Teflon (registered trademark) particles are mixed with a resin, so that the lip portion 33a is a rectilinear cylinder. It is possible to slide without being a large load with respect to the outer peripheral surface of the cylindrical body such as 5.

  The light shielding ring 31 is configured to be slidable by a predetermined amount with respect to the thrust direction and the rotation direction, and the surface of the light shielding sheet 33 is coated with Teflon (registered trademark) resin or the like. Therefore, the friction between the flange 3c and the light shielding sheet 33 when the lens barrel 1 is driven can be reduced, and the stress applied to the support 32 can be reduced. For this reason, the rigidity of the support body 32 can be maintained even if the plate thickness and the ring width of the support body 32 are reduced. In the present embodiment, the support 32 has a plate thickness of 0.2 mm, a ring width of 0.7 mm, a width of the ring portion of the light-shielding ring including the lip portion, and a plate in the optical axis direction including the lip portion. The thickness is as small as 0.3 mm. Note that the thickness of the support 32 may be reduced to a level of 0.01 mm, for example, to obtain a light-opaque property with respect to visible light if design rigidity is obtained.

  Therefore, the light shielding ring 31 is reduced in size to about 1/2 in the plate thickness and about 1/3 in the ring width as compared with the conventional light shielding ring.

  In this embodiment, the light shielding member 30 has the light shielding member 30 in addition to the light shielding ring 31. The light shielding member 30 has a high performance that sufficiently shields outside light even when the tubes are eccentric. Therefore, the structure can be simplified and the size can be easily reduced.

  As described above, according to the first embodiment of the present invention, the friction between the light shielding member and the lens barrel is small, and the structure is small and simple with respect to the optical axis direction of the lens and the radial direction of the lens barrel. It is possible to provide a lens barrel for a camera that shields light from each other and the space between the lens barrel and the exterior cover of the camera body.

  FIGS. 5B and 5C show other examples of the light shielding sheet 33 in the light shielding ring 31, respectively.

  As shown in the cross-sectional shape of the light shielding sheet 331 shown in FIG. 5B, the lip portion 331a is formed with a predetermined angle with respect to the support 32, and the tip portion of the lip portion 331a. Is different from the light shielding sheet 33 shown in FIG. 5A described above.

  Thus, the bending direction of the lip portion 331a is determined by forming the lip portion of the light shielding sheet so as to have a conical surface as a whole at a predetermined angle, and when the light shielding ring 311 is attached to the rectilinear cylinder 5, it is stable. The operation of the shading ring is obtained. Further, by forming the tip of the lip portion 331a in a semicircular shape, the corner portion is eliminated, and a smoother operation of the light shielding ring 331 can be obtained.

  Further, the light shielding ring 312 shown in FIG. 5C is formed such that the light shielding sheet 332 has an adhesive fixing portion 332b having a U-shaped cross section with respect to the indicator 32. A lip portion 332a extends vertically downward from the seat portion.

  By forming in this way, it is possible to realize a stronger fixing force of the light shielding sheet 332 to the support body 32.

  Of course, the lip portion can be fixedly molded to the indicator 32 only on the inner peripheral surface of the support. In this case, the thickness of the light shielding ring in the optical axis direction can be minimized.

  5 (a), 5 (b), and 5 (c), the protruding portion 33b formed of the same member as the lip portion is bonded to the inner peripheral surface of the support 32. 331b and the adhesive fixing portion 332b are configured such that even when the pressure is applied to the light shielding ring in an abnormal state and the metal support 32 is pressed against the rectilinear cylinder 5, the support 32 comes into contact with the rectilinear cylinder 5 and It is possible to prevent the outer peripheral surface of the rectilinear cylinder 5 from being damaged.

  In the present embodiment, as shown in FIGS. 5A, 5B, and 5C, the shape of the light-shielding sheet is such that protrusions 33b and 331b that are in contact with the entire inner periphery of the support 32 are bonded. Although the fixing portion 332b is provided, the same effect can be obtained if portions that abut on three or more locations on the inner peripheral surface of the support 32 are provided.

Next, FIG. 6 shows a lens barrel of the second embodiment of the present invention.
In the present embodiment, instead of the light shielding member 30 employed in the first embodiment, a ring-shaped member having an inner diameter slightly larger than the outer diameter of the rectilinear cylinder 5 on the inner peripheral surface of the distal end portion of the rotating cylinder 3. The point which protruded and formed the inward flange as the light shielding member 3f differs from the said 1st Embodiment. Since other configurations are substantially the same as those of the first embodiment, members having the same functions are denoted by the same reference numerals and description thereof is omitted.

  In the state shown in FIG. 6, the rectilinear cylinder 5 is eccentric with respect to the fixed cylinder 2, and the rotating cylinder 3 is eccentric with respect to the fixed cylinder 2, so that the rotating cylinder 3 and the rectilinear cylinder 5 are most eccentric. State.

  In this state, when external light is incident, the incident light is limited by the light shielding member 3 f provided at the front end of the rotating cylinder 3. At this time, the external light having the most angle with respect to the optical axis and indicated by an arrow in the drawing does not pass through the thickness l of the lip portion 33a which is sufficiently thick with respect to the thickness t of the lip portion 33a. Cannot enter. For this reason, as in the first embodiment described above, a sufficient light shielding effect can be obtained without forming the lip portion 33a to a thickness that can completely shield light directly.

  As described above, in the second embodiment, the light shielding member 30 employed in the first embodiment of the present invention described above can be formed by a flange provided in front of the lip portion 33a.

FIG. 7 shows a lens barrel of the third embodiment of the present invention.
In the third embodiment, the shape of the light shielding sheet employed is different from those of the first and second embodiments described above, and the light shielding sheet 33 is in front of the tip of the lip portion 33a that hangs downward in the natural state. A ring-shaped projecting piece 33c that projects toward the surface is formed. Since other configurations are the same as those of the second embodiment, the same members are denoted by the same reference numerals and description thereof is omitted.

  The state shown in FIG. 7 is the same as in the second embodiment described above, in which the rectilinear cylinder 5 is eccentric with respect to the fixed cylinder 2 and the rotary cylinder 3 is eccentric with respect to the fixed cylinder 2. The rotating cylinder 3 and the linear cylinder 5 are in the most eccentric state.

  When the light shielding ring 31 is incorporated in the rectilinear cylinder 5, the protruding piece 33c of the light shielding sheet 33 is disposed perpendicular to the optical axis. The external light that is directly incident without being shielded by the light shielding member 3f is first incident on the protruding piece 33c, but the light transmitted therethrough becomes scattered light. The light is completely shielded by the lip 33a connected to 33c. Therefore, also in this case, it is possible to obtain a sufficient light shielding effect without forming the lip portion 33a to have a thickness capable of completely shielding direct light.

  As described above, in this embodiment, the light-shielding portion can be formed with a simpler structure as in the second embodiment of the present invention described above.

  As described above, according to the above-described embodiment, the light shielding portion of the lens barrel is accommodated in a space of about ½ in the optical axis direction and about １ ／ in the radial direction space compared to the conventional light shielding portion. And can be very small. Moreover, since the light-shielding ring has a simple configuration, it can be manufactured by molding a ring-shaped plate material, and the manufacturing cost can be kept low. Also, with regard to the amount of operating force that has been a problem in the past, the thickness of the lip portion can be formed as thin as about 0.1 mm, so that the driving load during operation of the lens barrel can be reduced.

[Appendix]
The invention having the following configuration can be obtained according to the embodiment of the invention.

(1) a first lens barrel that is fixed or movable with respect to the camera body;
A second lens barrel fitted into the first lens barrel and provided so as to be relatively movable in the axial direction with respect to the first lens barrel;
The outer peripheral surface of the second lens barrel is provided near the fitting portion between the first lens barrel and the second lens barrel, has an outer diameter smaller than the outer diameter of the second lens barrel, and is elastically deformed. And a ring-shaped support body that is integral with the lip portion and has rigidity, and is positioned in the thrust direction with respect to the first lens barrel and is held displaceably in the radial direction. A light-shielding ring that shields light incident on the camera body from the gap between the first and second lens barrels;
A light-shielding member that is provided in front of the lip portion and shields incident light that passes through the thin-walled portion of the lip portion and enters the camera body;
A lens barrel characterized by comprising:

(2) The lens barrel according to appendix (1), wherein the light shielding member is a flange of a first barrel provided in front of the lip portion.

(3) The lens barrel according to appendix (1), wherein the light shielding member is a flange provided in front of the lip portion.

(4) The lens barrel according to appendix (1), wherein the light shielding member is disposed in front of the lip portion, is fixed to the first barrel, and is pressed against the outer periphery of the second barrel.

(5) The lens barrel according to appendix (1), wherein the lip portion is formed of rubber.

(6) The lens barrel according to appendix (5), wherein the lip portion is made of silicon rubber.

(7) The lens barrel according to appendix (5), wherein the lip portion is made of fluororubber.

(8) The lens barrel according to appendix (5), wherein the outer peripheral portion of the support does not have rubber forming the lip portion, and the outer peripheral portion of the support is exposed over the entire periphery. .

(9) The lens barrel according to appendix (1), wherein a sliding surface between the lip portion and the second barrel is lubricated.

(10) The lens barrel according to appendix (9), wherein the lubricating surface treatment is performed by painting or coating a resin material containing tetrafluoroethylene.

(11) The lens barrel according to appendix (9), wherein the lubricated surface treatment is performed by CVD coating of xylene.

(12) The lens barrel according to appendix (1), wherein the support of the light shielding ring is an opaque metal.

(13) The lens barrel according to appendix (12), wherein the support is phosphor bronze.

(14) The lens barrel according to appendix (12), wherein the support is stainless steel.

(15) The lens barrel according to appendix (1), wherein the support has a convex portion that engages with the concave portion of the first barrel.

(16) The lens barrel according to appendix (1), wherein the lip portion is fixed to the support by molding.

(17) The supplementary note (1), wherein a member having elasticity is provided on the peripheral surface on the second lens barrel side of the support so that the peripheral surface of the support does not contact the peripheral surface of the second lens barrel. Lens barrel.

(18) The lens barrel according to appendix (17), wherein the elastic member is formed integrally with the lip portion.

(19) The lens barrel according to appendix (1), wherein the first barrel is a fixed barrel that is fixed relative to the camera body at least during photographing.

  (20) The lens barrel includes the following.

First and second lens barrels that are movable relative to each other and in a state where one inner peripheral portion and the other outer peripheral portion overlap each other;
A light-shielding portion that is provided on one end portion side of the first lens barrel and shields light entering from the one end portion side in the use state;
The first lens barrel is provided closer to the other end of the first lens barrel than the light-shielding portion provided on the first lens barrel, and is elastically deformed by being pressed against the outer peripheral portion of the second lens barrel. A pressure-shielding light-shielding member that finally shields light that has passed through the light-shielding part of
(21) In the above (20),
The pressure-contact light-shielding member has a rigid ring-shaped support, and an elastic member that is fixed to the support and has a thin lip portion that presses against the outer peripheral surface of the second lens barrel by elastic deformation. ing.

(22) In the above (21),
The lip portion is positioned in the thrust direction with respect to the second lens barrel and is held so as to be displaceable in the radial direction.

(23) In the above (20),
The press-contact light-shielding member and the first lens barrel are configured to be movable in the optical axis direction of the first lens barrel, and are configured so that their rotation directions cannot rotate with respect to each other.

(24) In the above (20),
The pressure-shielding light-shielding member is provided with a rigid ring-shaped support having convex protrusions and is integrally provided with the ring-shaped support, and is elastically deformed to be in pressure contact with the outer peripheral surface of the second lens barrel. The pressure-shielding light-shielding member is movable in the optical axis direction of the first lens barrel, and the rotation directions are not mutually rotatable. A concave groove portion is formed so that the protrusion portion engages.

(25) In the above (21),
The lip portion protrudes toward the first lens barrel, has an inner diameter that is ring-shaped, and has a L-shaped cross section. When the lip portion is positioned by the second lens barrel during use, the L-shaped portion And a base portion supporting the L-shaped portion to double shield light.

(26) In the above (20),
The light shielding portion shields part or all of external light entering from a gap between the first lens barrel and the second lens barrel.

(27) In the above (20),
The light shielding portion is a flange portion formed on the first lens barrel.

(28) In the above (27),
The flange portion is provided with an elastic member that comes into pressure contact with the outer peripheral surface of the second lens barrel and shields light first.

  (29) The lens barrel includes the following.

A first lens barrel fixed or movable with respect to the camera body;
A second lens barrel provided in the first lens barrel so as to be relatively movable in the axial direction with respect to the first lens barrel;
A light-shielding portion that is provided on one end portion side of the first lens barrel and shields incident light from the one end portion side in the use state;
The first lens barrel is provided closer to the other end of the first lens barrel than the light-shielding portion provided on the first lens barrel, and is elastically deformed by being pressed against the outer peripheral portion of the second lens barrel. A pressure-shielding light-shielding member that finally shields light that has passed through the light-shielding part of
(30) In the above (29),
The pressure-contact light-shielding member has a rigid ring-shaped support, and an elastic member that is fixed to the support and has a thin lip portion that presses against the outer peripheral surface of the second lens barrel by elastic deformation. ing.

(31) In the above (30),
The light-shielding portion provided in the first lens barrel reduces the amount of external light entering from the gap between the first lens barrel and the second lens barrel, and the outside that reaches the vicinity of the thin lip portion. Reduce the amount of light.

(32) In (30) above,
The elastic member is not present on the outer periphery of the support, and the outer periphery of the support is exposed.

(33) In the above (29),
The pressure-shielding light-shielding member includes a rigid ring-shaped support body having convex protrusions, and a lip that is provided integrally with the ring-shaped support body and that is in elastic contact with the outer peripheral surface of the second lens barrel. The pressure-contact light-shielding member is movable in the optical axis direction of the first lens barrel, and the rotation directions are mutually non-rotatable. A concave groove portion is formed so that the protrusion portion engages.

The center longitudinal cross-sectional view of the camera which has a lens barrel by this invention concerning the 1st Embodiment of this invention, An enlarged cross-sectional view of a main part of a light shielding portion provided in the lens barrel of FIG. 1; Sectional drawing which follows the II line in the said FIG. A perspective view of the shading ring, Main part sectional view showing the sectional shape of the lip part, The principal part expanded sectional view of the light-shielding part in the lens barrel which shows the 2nd Embodiment of this invention, The principal part expanded sectional view of the light-shielding part in the lens barrel which shows the 3rd Embodiment of this invention, The principal part expanded sectional view which shows an example of the light-shielding member in the conventional lens barrel,

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lens barrel 2 ... Fixed barrel (1st barrel)
3 ... Rotating tube (first barrel)
5 ... Straight tube (second barrel)
30 ... Shading member 31 ... Shading ring 32 ... Support 33a ... Lip part

Claims (1)

A first lens barrel having a first notch step for arranging a light shielding member;
Forming a space together with the first notch step portion, a second lens barrel rotating with respect to the first lens barrel; and
A third barrel that moves in the optical axis direction relative to the first barrel in conjunction with the rotational movement of the second barrel;
A first light-shielding member having a ring-shaped inward flange having an inner diameter slightly larger than the outer diameter of the third lens barrel, protruding from the inner peripheral surface of the distal end portion of the second lens barrel;
A ring-shaped support having a rotation stop projection for engaging with the groove of the first lens barrel, and an outer peripheral surface of the third lens barrel provided integrally with the support and elastically deforming. A second light shielding member disposed in a space formed by the second lens barrel and the first cut-in step portion,
Comprising
The support that forms the second light shielding member is engaged with the groove portion of the first lens barrel so as not to rotate more than a predetermined amount with respect to the first lens barrel, and further, the third mirror When the tube moves in the optical axis direction with respect to the first lens barrel, the third lens barrel is disposed so as to be relatively movable in the optical axis direction,
The light shielding sheet has the ring-shaped inward flange when the support is moved in the optical axis direction and the radial direction by the third lens barrel being eccentric with respect to the optical axis. A lens barrel characterized in that a light beam entering the camera body is shielded from a gap between a light shielding member and the outer peripheral surface of the third lens barrel.

Images