JP2000356730A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely surround a gap between a lens holding frame and a lens barrel frame by a bellows-like light shielding and dustproofing rubber to prevent light beam and a foreign matter such as sand from entering even if the accuracy of parts and the standby position of the lens holding frame vary. SOLUTION: The lens holding frame 12 is moved forward and backward in the optical axis direction by holding a photographing lens 11. The lens barrel frame 28 is constituted so as to cover the frame 12 and provided with an aperture part 28b to the lens 11. Then, the bellows-like light shielding and dustproofing rubber 30 elongates and contracts by following the forward and backward movement of the frame 12 so as to surround a gap between the frames 12 and 28. When the back end of the rubber 30 is held at the flange part 12d of the frame 12 and the front end is held at the flange part 28a of the frame 28 by a pressing plate 31 piercing through the aperture part 28b of the frame 28, the whole length of the rubber 30 is set to be longer than the length L2 between the plate 31 and the flange part 12d of the frame 12 standing by at the most restored position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel having a light-shielding / dust-proof member for preventing light and small foreign substances such as sand and dust from entering the lens barrel.

[0002]

2. Description of the Related Art Heretofore, a light-shielding / dustproof member for preventing a light beam and small foreign substances such as sand and dust from entering a lens barrel has been disclosed in Japanese Patent Application No. 9-241707 filed by the present applicant. I have. The configuration of the light-shielding / dustproof member described in Japanese Patent Application No. 9-241707 includes a flange portion of a lens holding frame that holds a photographing lens and moves forward and backward in the optical axis direction, and a lens barrel frame that covers the lens holding frame. An elastic bellows-like light-shielding / dustproof rubber is disposed between the flange portion and the light-shielding / dustproof rubber. The light-shielding / dustproof rubber surrounds a gap between the lens holding frame and the lens barrel frame, and follows the lens holding frame. It expands and contracts.

[0003]

However, in the above-described conventional configuration, since there is no disclosure regarding the total length of the light-shielding / dust-proof rubber, the dimensional accuracy of each component is not uniform, and the standby position of the lens holding frame is not disclosed. Due to the variation of
There is a problem in that a gap is generated between the lens holding frame and the lens barrel frame, and light rays and small foreign substances such as sand and dust enter the frame.

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a lens barrel which can reliably prevent light and small foreign substances such as sand and dust from entering.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention is directed to a method in which a lens holding member for holding a photographing lens, which is movable back and forth, and a supporting member for supporting the lens holding member are provided. The length of the bellows-like light-shielding / dustproof member is made longer than the length between the holding member on the support member side of the light-shielding / dustproof member and the supporting portion of the lens holding member so as to expand and contract following the movement of the holding member. is there.

[0006]

According to the first aspect of the present invention, there is provided a lens holding member which is movable back and forth in the optical axis direction and stands by at a retracted position, and has an opening for the taking lens which supports the lens holding member. A bellows-like light shield that is located between the support member and the lens holding member and surrounds the gap between the lens holding member and the support member and that expands and contracts following the forward and backward movement of the lens holding member. In a lens barrel provided with a dust-proof member, the total length of the light-shielding / dust-proof member is longer than the length between the holding member for holding the light-shielding / dust-proof member on the support member side and the supporting portion of the lens holding member. With this setting, when the light-shielding / dustproof member is incorporated between the support member and the lens holding member, the light-shielding / dustproof member can be charged in advance, so that the dimensional accuracy of each component and the lens holding member In the standby position Even if luck, the lens holding member and the support member and the gap can be reliably encloses the, small foreign matter from entering, such as light and sand, dust to the lens barrel inside can be reliably prevented.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an exploded perspective view of a shutter / focus unit disposed in a lens barrel of the present embodiment,
2 is an exploded perspective view of a lens barrel provided with a light-shielding / dustproof rubber, FIG. 3 is a side view of the light-shielding / dustproof rubber, FIG. 4 is a longitudinal sectional view of the lens barrel, and FIG. FIG. 3 is a longitudinal sectional view of the lens barrel in a state. First, the configuration of the shutter / focus unit 1 will be described with reference to FIG.
Reference numeral 2 denotes a shutter unit which includes a shutter base plate 3 having a shooting opening 3a formed therein, a shutter blade 4 disposed behind the shutter base plate 3, and a holding plate 5 for holding the shutter blade 4 on the shutter base plate 3. And a shutter blade driving actuator 6 arranged in front of the shutter base plate 3.

Reference numeral 7 denotes a focus gear, which is a motor 1 to be described later.
7 is transmitted to a feed screw 15 described later. The focus gear 7 is rotatably fitted and supported on a gear shaft 3b formed on the shutter base plate 3, and is supported by a focus base plate 8 described later. 8 is a focus ground plate, 2
It is fixed to the shutter base plate 3 by a book screw 9.
Reference numeral 10 denotes a photographing lens unit which is pressed into a photographing lens 11, a lens holding frame (lens holding member) 12 for holding the photographing lens 11, and an arm 12a formed on a part of the outer periphery of the lens holding frame 12. A fixed hollow cylindrical fitting metal 13 and a pulse plate 14 fixed by bonding
It is composed of

Reference numeral 15 denotes a feed screw which is arranged in parallel with the photographing optical axis to move the photographing lens unit 10 back and forth in the direction of the optical axis. A gear 15a and a male screw 15b are formed at each end. Shafts 15c and 15d are formed. The gear 15a is connected to the focus gear 7
The male screw 15b meshes with the female screw 16a formed on the nut 16, and the shaft 15c penetrates the hole 8a formed on the focus ground plate 8 into the hole 3c formed on the shutter ground plate 3. The shaft 15d is rotatably supported by passing through a hole 12b formed in the arm portion 12a of the lens holding frame 12 and fitting into a hole 19b formed in a support base plate 19 to be described later. The photographing lens unit 10 is supported by the shutter unit 2. Note that the nut 16 is provided on the notch 1 formed in the arm 12a of the lens holding frame 12.
2c, the nut 16 and the photographic lens unit 10 are connected to the male screw 15a of the feed screw 15 by the engagement between the female screw 16a and the male screw 15b of the feed screw 15.
It moves back and forth in the optical axis direction along the lead b.

Reference numeral 17 denotes a cylindrical motor, which is a drive source for moving the photographing lens unit 10 back and forth in the optical axis direction. A pinion gear 17a incorporated at the tip of the drive unit meshes with the focus gear 7. The motor 17 is disposed in parallel with the photographing optical axis, and its rear portion is formed in a hole 8b formed in the focus base plate 8 and its front portion is formed in a hole 19c formed in a support base plate 19 described later, respectively. The fitting is supported by the shutter unit 2. Reference numerals 18 and 21 are guide shafts arranged in parallel with the photographing optical axis and supporting the photographing lens unit 10 in the optical axis direction. The guide shaft 18 is supported by fitting a rear portion thereof into a hole 8c formed in the focus base plate 8 and a front portion thereof into a hole (not shown) formed in the support base plate 19, respectively. The lens holding frame 12 is slidably fitted with a U-shaped notch (not shown) formed at a position facing the arm 12a. On the other hand, the guide shaft 21 has a rear portion formed in a hole 8d formed in the focus base plate 8 and a front portion formed in an adjustment plate 23 to be described later through a hole 19d formed in the support base plate 19. Each of the holes 23 a is supported by being fitted thereto, and is slidably fitted with the fitting metal 13 fixed to the lens holding frame 12.

Reference numeral 19 denotes a support base plate which supports the photographing lens unit 10, the feed screw 15, the motor 17, and the guide shaft 18, and which is fixed to the shutter base plate 3 and the focus base plate 8 by three screws 20. Fixed. Reference numeral 22 denotes a lens spring, which penetrates the hole 19d of the support base plate 19, is disposed between the arm portion 12a of the lens holding frame 12 and an adjustment plate 23 described later, and urges the photographing lens unit 10 backward. ing.

Reference numeral 23 denotes a tilt adjustment plate which adjusts the tilt of the taking lens unit 10 with respect to the center of the optical axis, and is fixed to the support base plate 19 by screws 25 via washers 24. Reference numeral 26 denotes an eccentric shaft for operating the tilt adjustment plate 23, and a hole 19 formed in the support base plate 19 is provided.
e and a hole 23b formed in the tilt adjustment plate 23 so as to be rotatable, and is held by the support base plate 19 by the tilt adjustment plate 23.

As shown in FIGS. 2 to 4, the shutter / focus unit 1 having the above structure has a flange portion 28 formed on a lens barrel frame (support member) 28 by three screws 29.
It is covered by being fixed to a. The flange 28a of the lens barrel frame 28 has an opening 28b set to be larger than the outer diameter of the light-shielding / dustproof rubber 30, which will be described later. Is two straight keys 2
8d are formed respectively. Reference numeral 30 denotes an elastic bellows-like light-shielding / dust-proof rubber (light-shielding / dust-proof member), which is an opening 28b of the lens barrel frame 28 and an opening 19a of the support member 19.
, One end of which is held by a flange portion 12d formed on the lens holding frame 12 and the other end of which is held by a pressing plate 31 described later, and expands and contracts in accordance with the longitudinal movement of the lens holding frame 12. The light-shielding / dustproof rubber 30 is located between the lens holding frame 12 and the lens barrel frame 28 and
The lens frame 8 surrounds the gap between the lens 8 and the lens holding frame 12 to prevent light rays and small foreign matter such as sand and dust from entering the lens barrel. At this time, the total length L1 of the light-shielding / dustproof rubber 30 shown in FIG. 3 is the length L between the holding plate 31 and the flange portion 12d of the lens holding frame 12 which stands by at the most retracted position.
It is set longer than 2.

Reference numeral 31 denotes a holding plate (holding member) which is disposed in front of the flange portion 28a of the lens barrel frame 28, and
The dustproof rubber 30 is held, and an opening 31a smaller than the outer diameter of the light-shielding / dustproof rubber 30 is formed. The light-shielding / dustproof rubber 30 is charged in advance by holding the holding plate 31. Numeral 32 denotes a barrier drive ring, which is disposed in front of the flange portion 28a of the lens barrel frame 28, and is fitted and supported on the inner periphery of the lens barrel frame 28 so as to be rotatable around the photographing optical axis. Is transmitted to a barrier device 34 described later, and the two barrier blades 36 are opened and closed. A barrier drive ring spring 33 is disposed above and below the barrier drive ring 32 and urges a barrier blade 36 of the barrier device 34 in an opening direction. One end of the barrier drive ring spring is attached to the flange 28 a of the lens barrel frame 28. The other end is hung on the formed shaft 28 e on a hook 32 a formed on the barrier drive ring 32.
Reference numeral 34 denotes a barrier device, which is disposed in front of the barrier drive ring 32 and is fixed to the lens barrel frame 28. At least two barrier devices are provided to open and close a barrier base plate 35 and an opening 35a formed in the barrier base plate 35. It comprises a barrier blade 36, a barrier spring (not shown) for urging the barrier blade 36 in the opening direction, and a fixing plate 37 for fixing the barrier blade 36 to the barrier base plate 35.

The focus driving of this embodiment having the above-described configuration will be described. When the photographing lens unit 10 is extended from the state shown in FIG. 4, when the motor 17 is energized, the motor 17 rotates the pinion gear 17a. The rotational force of the pinion gear 17a is transmitted to the gear 15a of the feed screw 15 via the focus gear 7 to rotate the feed screw 15, and the photographing lens unit 10 moves along the lead of the male screw 15b of the feed screw 15 via the nut 16. While the lens spring 22 and the light-shielding / dustproof rubber 30 are being charged, the interior of the lens barrel frame 28 is moved in the optical axis direction as shown in FIG.

On the other hand, when the photographing lens unit 10 is retracted from the state shown in FIG. 5, the photographing lens unit 10 is driven via a nut 16 by the lead of the male screw 15 b of the feed screw 15 by performing a driving reverse to the above-mentioned extending operation. along,
As shown in FIG. 4, the lens barrel 28 moves in the optical axis direction in the lens barrel frame 28.
At this time, the light-shielding / dust-proof rubber 30 extends following the photographing lens unit 10 by using the repulsive force when charged.

Further, according to the present embodiment, the total length L1 of the light-shielding / dustproof rubber 30 is set between the flange portion 12d of the lens holding frame 12 when the light-shielding / dustproof rubber 30 is fully retracted and the holding plate 31. Is set to be longer than the length L2, so that the light-shielding / dustproof rubber 30 is
The light-shielding / dustproof rubber 30 can be charged in advance when it is incorporated between the second flange portion 12d and the lens holding member, even if the dimensional accuracy of each component and the standby position of the lens holding frame 12 vary. The gap between the frame 12 and the lens barrel frame 28 can be reliably surrounded, and light rays and small foreign matters such as sand and dust can be prevented from entering the lens barrel.

FIGS. 6 and 7 show an example of a zoom lens barrel in which the light-shielding / dustproof rubber 30 having the above-described configuration is incorporated. The same parts as those in the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numeral 40 denotes a fixed cylinder, which is fixed to the camera body 48 by a screw 47, and has a helicoid screw 40a, two rectilinear grooves 40b, and a hole 40c extending in the optical axis direction formed on the inner periphery thereof. Reference numeral 41 denotes a first rotary cylinder, which is rotatably supported on the outer periphery of a first rectilinear cylinder 42 described later, and a helicoid screw 41a formed at the outer rear end of the first rotary cylinder meshes with a helicoid screw 40a of the fixed cylinder 40. Due to this engagement, the fixed cylinder 40 is supported by the fixed cylinder 40 and moves back and forth in the optical axis direction while rotating along the lead of the helicoid screw 40a of the fixed cylinder 40. The first rotary cylinder 4
A gear portion 41c is formed on the first helicoid screw 41a, and two straight grooves 41b are formed in the inner peripheral portion thereof.

Reference numeral 42 denotes a first rectilinear cylinder, and the first rotary cylinder 41
, And moves back and forth in the optical axis direction integrally with the first rotary cylinder 41. At this time, in the first rectilinear cylinder 42, two convex portions 42b formed on the flange portion 42a at the rear end thereof are slidably fitted in the two rectilinear grooves 40b of the fixed cylinder 40. , And moves back and forth in the optical axis direction using the two rectilinear grooves 40b as guides. Further, three cam grooves 42c and two rectilinear grooves 42d are formed on the inner peripheral surface of the first rectilinear cylinder 42, and two cam grooves 42c having the same lead angle as the three cam grooves 42c are formed. Are formed. A second rotary cylinder 43 is rotatably supported on the outer periphery of a second rectilinear cylinder 45 described later, and three cam shafts 43a formed on the rear end of the outer periphery thereof have three camshafts 43a of the first rectilinear cylinder 42. The three camshafts 43a are slidably fitted in the cam grooves 42c, are supported by the first rectilinear barrel 42 by fitting the three camshafts 43a, and extend along the cam grooves 42c of the first rectilinear barrel 42. Move back and forth in the optical axis direction while rotating. Further, three cam grooves 43b and 43c are formed on the inner periphery of the second rotary cylinder 43, respectively.

Reference numeral 44 denotes a transmission shaft for transmitting the rotational force of the first rotary cylinder 41 to the second rotary cylinder 43, which is attached to the rear end of the second rotary cylinder 43, and The first rotary cylinder 4 penetrates through the two cam holes 42 e of the rectilinear cylinder 42.
One of the two rectilinear grooves 41b is slidably fitted. 4
Reference numeral 5 denotes a second rectilinear cylinder, which is supported on the inner peripheral side of the second rotary cylinder 43, and moves back and forth in the optical axis direction integrally with the second rotary cylinder 43. At this time, in the second rectilinear cylinder 45, two convex portions 45b extending in the outer peripheral direction formed on the flange portion 45a at the rear end thereof are slidable in the two rectilinear grooves 42d of the first rectilinear cylinder 42. Because of the engagement, the second rectilinear barrel 45 moves back and forth in the optical axis direction with the two rectilinear grooves 42d of the first rectilinear barrel 42 serving as guides. The second rectilinear barrel 45 has three rectilinear holes 45c penetrating therethrough, and two rectilinear grooves 45d formed on the outer periphery.

Reference numeral 46 denotes a second lens holding frame, which includes three camshafts 46 formed at the distal end of a convex portion 46a projecting from the outer peripheral portion.
b penetrates through the three rectilinear holes 45c of the second rectilinear cylinder 45 and is slidably fitted into the three cam grooves 43b of the second rotary cylinder 43. By fitting these three cam shafts 46b, the second lens holding frame 46 is supported by the second rotary cylinder 43 and moves back and forth in the optical axis direction along the cam grooves 43b of the second rotary cylinder 43. I do. At this time, since the three cam shafts 46b of the second lens holding frame 46 are slidably fitted in the three rectilinear holes 45c of the second rectilinear barrel 45,
The rectilinear cylinder 45 is moved back and forth in the optical axis direction using the three rectilinear holes 45c as guides.

The lens barrel frame 28 has three cam shafts 28c formed at the rear end thereof slidably fitted in the three cam grooves 43c of the second rotary cylinder 43. By this fitting, the lens barrel frame 28, the shutter / focus unit 1 and the photographing lens unit 10 supported by the lens barrel frame 28 are supported by the second rotary barrel 43, and the second rotary barrel 43 It moves back and forth in the optical axis direction along the cam groove 43c. At this time, since the two rectilinear keys 28d formed on the inner peripheral portion of the lens barrel frame 28 are slidably fitted in the two rectilinear grooves 45d of the second rectilinear cylinder 45, 2 straight barrel 4
5 is moved back and forth in the optical axis direction with the straight groove 45d as a guide. Reference numeral 49 denotes a drive unit, which includes a motor 51 having a gear 51a fixed to a gear base plate 50 and gears 52a to 52
f is rotatably fitted to and supported by a gear base plate 50, and is held by a pressing plate (not shown).
Through the hole 40c, and the gear portion 41 of the first rotary cylinder 41
It is engaged with c.

The operation of the zoom lens barrel having the above configuration will be described. When a zoom switch (not shown) provided on the camera body 48 is switched between the wide direction and the tele direction, the motor 51 rotates, and the rotational force of the gear 51a is changed to the gear 5a.
The power is transmitted to the first rotary cylinder 41 via 2a to 52f. The first rotary cylinder 41 to which the rotational force is transmitted rotates the outer circumference of the first rectilinear cylinder 42 while the helicoid screw 40 a of the fixed cylinder 40 is being rotated.
Along the lead of the optical axis. At this time, the first rectilinear tube 42 moves back and forth while moving straight in the optical axis direction with the rectilinear groove 40b of the fixed tube 40 as a guide.

The torque of the first rotary cylinder 41 is transmitted to the second rotary cylinder 43 via two transmission shafts 44. The second rotary cylinder 43 to which the torque has been transmitted moves back and forth in the optical axis direction along the three cam grooves 42c of the first linear cylinder 42 while rotating around the outer periphery of the second linear cylinder 45. . At this time, the second
The rectilinear barrel 45 moves back and forth while traveling straight in the optical axis direction using the two rectilinear grooves 42d of the first rectilinear barrel 42 as a guide. The rotation of the second rotary cylinder 43 causes the second lens holding frame 46 to move into the three cam grooves 43 b of the second rotary cylinder 43.
Further, the lens barrel frame 28 and the shutter / focus unit 1 and the photographing lens unit 10 supported by the lens barrel frame 28 move along the cam groove 43c of the second rotary barrel 43 in the optical axis direction, respectively. Move back and forth. At this time, the second
The lens holding frame 46 and the lens barrel frame 28 are
The book is moved back and forth in the optical axis direction using the straight hole 45c as a guide.

[0025]

As described above, according to the first aspect of the present invention, there is provided a lens holding member which is movable back and forth in the optical axis direction and stands by at a retracted position, A support member having an opening, located between the lens holding member and the support member, surrounding a gap between the lens holding member and the support member, and expanding and contracting following the forward and backward movement of the lens holding member. In a lens barrel provided with a bellows-like light-shielding / dustproof member, the entire length of the light-shielding / dustproof member is set between the holding member for holding the light-shielding / dustproof member on the support member side and the supporting portion of the lens holding member. By setting the length to be longer than the length, when the light-shielding / dustproof member is incorporated between the support member and the lens holding member, the light-shielding / dustproof member can be charged in advance, so that the dimensional accuracy of each component and Lens holding member Even if the standby position fluctuates, the gap between the lens holding member and the support member can be reliably surrounded, and light rays and small foreign substances such as sand and dust can be reliably prevented from entering the lens barrel. it can.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a shutter / focus unit used for a lens barrel according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a lens barrel in which a light-shielding / dustproof rubber is arranged.

FIG. 3 is a side view of the light-shielding / dustproof rubber.

FIG. 4 is a longitudinal sectional view of the lens barrel in a state where the lens holding frame stands by at a position where the lens holding frame is most retracted.

FIG. 5 is a longitudinal sectional view of the lens barrel with the lens holding frame extended.

FIG. 6 is a longitudinal sectional view of a zoom lens barrel in which a light-shielding / dustproof rubber is incorporated as a usage example of the lens barrel.

7 is a front view of a main part of a camera incorporating the zoom lens barrel of FIG. 6;

[Explanation of symbols]

1... Shutter shutter focus unit, 10. photographing lens unit, 11. photographing lens, 12. lens holding frame (lens holding member), 12d flange section, 17
..Motor, 19..support base plate, 19a..opening, 2
8. Barrel frame (supporting member), 28a Flange part, 2
8b: opening, 30: light-shielding / dust-proof rubber (light-shielding / dust-proof member), 31: holding plate (holding member), 31a: opening.

Claims (1)

[Claims] 1. A lens holding member which can move back and forth in the optical axis direction and stands by at a retracted position, a supporting member which supports the lens holding member and has an opening for a photographing lens, the lens holding member and the support A lens barrel having a bellows-like light-shielding / dustproof member that is located between the lens holding member, surrounds a gap between the lens holding member and the support member, and expands and contracts according to the forward and backward movement of the lens holding member. A lens mirror, wherein a total length of the light-shielding / dustproof member is set to be longer than a length between a holding member for holding the light-shielding / dustproof member on the support member side and a supporting portion of the lens holding member. Tube.