JPH09211533A - Lens barrel and optical instrument using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an optical member having a shutter unit and a lens holding member to surely perform pressing toward a one side without using a special space and to miniaturize a camera and to secure optical performance by arranging two springs having small winding diameter on a dead space occurring inside a shutter blade operating area. SOLUTION: The one-side pressing springs 142 and 143 are formed inside the notched parts 105d and 105e of a shutter base plate 105, and the parts of the springs on a rear side in an optical axis direction are housed inside nearly U-shaped notched parts 105f and 105g covered by the shutter base plate 105 as abutting surfaces of the springs 142 and 143. The set position of the part 105f is on a blade rotation center side from the leading end inside diameter part 106c of the shutter spring 106 so that the spring 106 does not interfere in the case of total closing, and is further outside from the outside part 107d of the blade in the case the shutter blade 10 totally opens so that the shutter blade 107 does not interfere in the case of total opening.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel and an optical device using the lens barrel, and particularly for zooming (zooming).
Alternatively, a lens group holding lens barrel (lens group holding member) holding a focusing lens group can be moved smoothly and accurately on the optical axis during zooming or focusing while effectively utilizing space. It is suitable for an optical device such as a video camera or a film camera capable of performing the above.

[0002]

2. Description of the Related Art Conventionally, in a lens barrel of an optical device such as a video camera or a film camera, a lens group holding lens barrel holding a lens group for zooming or focusing is driven by a driving force from a driving means such as a motor. Is moved on the optical axis.
In the lens barrel of such an optical device, the lens group holding barrel is biased in one direction on the optical axis by using an elastic member such as a spring.

Conventionally, as a method of biasing the lens holding members at this time, a compression spring (commonly called a surprise spring) whose winding diameter is increased so as not to enter the photographing optical path is arranged between the lens holding members. Utilizing the urging force of the surprise spring, each lens holding member is urged in a direction away from the optical axis direction, thereby eliminating the backlash of each lens holding member.

[0004]

According to the conventional method of biasing the lens holding members, since the surprise springs having a large winding diameter are arranged between the lens holding members, the space for accommodating the surprise springs is reduced according to the reduction of the lens group interval due to zooming. Needed to be secured.

In general, since a surprise spring has a large winding diameter,
It is necessary to increase the wire diameter in order to generate the required force. For this reason, there is a problem that the storage space for the surprise spring tends to be large, and the entire camera becomes large in order to secure this storage space.

According to the present invention, the lens holding member is arranged in a predetermined direction while the size of the entire device is reduced by appropriately disposing the biasing elastic member in an area which is not used in the conventional lens barrel. It is an object of the present invention to provide a lens barrel and an optical device using the lens barrel, which can accurately shift the lens holding member accurately during zooming or focusing.

[0007]

The lens barrel of the present invention comprises (1-1) at least two shutter blades (106,
Shutter unit (105, 10) having 107)
6, 107, 114) is fitted with a lens holding member (104) so as to relatively move in the optical axis direction, and a notch (105f, 105f,
105g) has elastic members (142, 143) in which one end of the elastic member abuts on a part of the shutter unit and the other end abuts on a part of the lens holding member so that the shutter unit and the lens holding member are in the optical axis direction. And the shutters outside the outer shape (107d) of one shutter blade (107) and the other shutter when the cutout portions (105f, 105g) fully open the shutter blades of the shutter unit. It is characterized in that it is positioned within a shutter blade non-use area (Y1) formed with the inner side (106c) of the operation amount outline of the blade (106).

In particular, (1-1-1) At least two elastic members are provided.

(1-1-2) At least two areas where the shutter blades are not used are formed so as to sandwich the optical axis.

The optical device of the present invention has the constitutional requirement (1-1).
It is characterized in that image information is formed on a predetermined surface by using the lens barrel.

[0011]

FIG. 1 is a perspective view of a main part of a first embodiment of the present invention. 2 to 5 are development explanatory views of a part of FIG. 1, FIG. 6 is a schematic view of a part of FIG. 1, FIG. 7 is a cross-sectional view of a main part of the lens barrel of the present embodiment in a collapsed state, FIG. 8 and FIG. 9A and 9B are cross-sectional views of main parts of the photographing system of the present embodiment at the wide-angle end and the telephoto end, respectively.

In the figure, 101 is a first group lens holder for holding a first group lens (not shown), and 102 is a first group lens barrel for holding the first group lens holder 101. 1
Reference numeral 03 denotes a second lens group holder that holds a second lens group (not shown), and 104 denotes a second lens group lens barrel (lens holding lens barrel) that holds the second lens group holder 103.

Reference numeral 105 denotes a shutter base plate which constitutes one element of the shutter unit. Two shutter blades 106, 107 are provided on the front side of the optical axis, and a rotation center hole 106 thereof.
rotation support shaft 10 rotatably supported around a and 107a
5a and 105b are formed. Also shutter blade 1
Driven holes 106b, 10 for engaging the drive pin 108a of the shutter drive magnet 108 with 06, 107.
7b is formed.

The shutter drive magnet 108 has a rotation center hole 108b at one end rotatably supported by a rotation support shaft (not shown) of the shutter base plate 105, and a rotation center shaft 108c at the other end side is a support hole for the magnet cover 109. It is rotatably supported (not shown). The shutter blade 1 is rotated by the rotation of the shutter drive magnet 108.
By rotating the 06 and 107, the shutter base plate 10
The aperture opening 105c formed around the optical axis of No. 5 is opened and closed to properly expose the film (photosensitive surface). The shutter drive magnet 108 is composed of a two-pole magnetized ferrite magnet, and is rotationally driven by the action of the following magnetic circuit.

Reference numerals 110, 111 and 112 denote yokes forming closed magnetic paths, and reference numeral 113 denotes yokes 110, 111 and 112.
It is a drive coil that generates a magnetomotive force. York 112
Foot portions 112a and 112b in the optical axis direction and the yoke 110,
When the foot portions 110a and 111a of the optical axis 111 of the 111 are assembled,
The drive coil 113 is fitted into the central opening 113a of the drive coil 113 while being offset from each other by the plate thickness thereof, thereby forming a closed magnetic circuit. By appropriately energizing the drive coil 113 in the assembled state as described above, the yokes 110, 111
Magnetic poles are formed on the magnet facing pole teeth 110b and 111b, and the shutter drive magnet 108 is rotationally driven to open / close the shutter.

A blade partition plate 114 is arranged further forward of the optical axes of the shutter blades 106 and 107, and the shutter blade 1 is provided between the blade partition plate 114 and the shutter base plate 105.
06 and 107 are slidably held. The shutter base plate 105, the shutter blades 106 and 107, the blade partition plate 114, and the like constitute one element of the shutter unit.

On the front side of the optical axis of the blade partition plate 114, a variable diaphragm 11 for variably controlling the fully open diaphragm diameter by zooming.
5,116 are arranged. The variable diaphragms 115 and 11
The holes 115a and 116a formed at the center of rotation of 6 are the rotation support shafts 105a formed on the shutter base plate 105,
It is rotatably supported by 105b. Therefore, the blade partition plate 114 is formed with escape holes 114a and 114b so that the rotary support shafts 105a and 105b can pass therethrough.

A biasing spring 117 is hooked on each of the spring hooks 115b and 116b in the direction in which the variable diaphragms 115 and 116 rotate in the closing direction, so that the variable diaphragms 115 and 116 are always biased in the closing direction. The variable diaphragms 115 and 116 further have a hemispherical diaphragm formed at a position projecting from the outermost circumference of the shutter base plate 105 to the outside.
5c and 116c are formed. The hemispherical projections 115c and 116c are assembled into the first group lens barrel 10
Two cam parts 102a, 1 formed on the inner peripheral corresponding part of 2
02b is pressed by the action of the biasing spring 117.

The positions of the projections 115c and 116c are regulated along the cams 102a and 102b by the relative position change in the optical axis direction due to zooming. As a result, the fully open aperture shape is the focal length due to zooming of the photographing system. It is configured to change according to. Further, the surfaces 102c and 102d on the opposite side of the cam portions 102a and 102b.
Is a hemispherical projection 115c, 116c of the variable diaphragm 116
And an escape cam that escapes the movement range of, and is formed substantially along the optical axis direction.

Reference numeral 118 is a variable diaphragm pressing member. The variable diaphragm holding member 118 holds the variable diaphragms 115 and 116 slidably with the blade partition plate 114, and is fixed to the shutter base plate 105 with screws or the like (not shown).

Reference numeral 119 is a third lens group holder for holding a third lens group (not shown), and 120 is a guide bush. The guide bush 120 is fixed to the opening hole 119a of the third lens group holder 119 by press fitting or the like. 1
Reference numeral 21 denotes a third group guide bar, which is the guide bush 1
20 is slidably fitted to the third lens group holder 119.
Is held so as to be movable in the optical axis direction.

Reference numeral 122 denotes a third group steady rest bar,
A notch 119b for engagement of the group lens holder 119 is slidably held. The action of the third group guide bar 121 and the third group steadying bar 122 causes the third group lens holder 119 to move substantially parallel to the optical axis. Third
The rear end portion 121a of the group guide bar 121 in the optical axis direction is held in the engagement hole 123a of the rear base plate 123, and the front end small diameter portion 12
1b is engaged and held in an engaging hole 124a of the third group tilt adjusting plate 124. Shutter main plate 105 and rear main plate 123
Is fixed by a known means such as a screw, and the third group tilt adjusting plate 124 is fixed by a screw or the like while sandwiching a known wave washer on the variable diaphragm pressing member 118, and can be moved by an amount determined by an eccentric pin or the like. It's done like this. The tilt of the third lens group due to various component tolerances is corrected by the action of the third lens group tilt adjusting plate 124.

Reference numeral 1230 is a third group biasing spring,
It is arranged coaxially with the group guide bar 121, one end of which is the third group tilt adjusting plate 124 and the other end is the third group lens holder 119.
It comes into contact with the end face of the press-fitting portion of the guide bush 120, and serves to constantly bias the third lens group holder 119 in the rearward direction of the optical axis.

Next, each element of the stepping motor for driving the third lens group holder 119 in the longitudinal direction of the optical axis will be described. 1240 and 125 are yokes and coil 1
26 is fitted in each of the bent portions 1240a and 125a to form one closed magnetic path.

Similarly, the yokes 127 and 128 are also coils 12.
9 are fitted into the respective bent portions 127a and 128a to form one closed magnetic path. Each york 1
Magnet facing pole teeth 1240b, 125b, 127b, 128b formed on 25, 1240, 127, 128
A third group feed screw 131 is arranged on the central axis of the. A magnet 130 having 10 poles is fixed to the third group feed screw 131 with an adhesive or the like, and is rotatably held on the shutter base plate 105 on the front side of the optical axis and on the rear base plate 123 on the rear side.

Reference numeral 132 is a feed nut. The feed nut 132 is the nut receiving portion 1 of the third lens group holder 119.
It is held by 19c and is further screwed to the third group feed screw 131. Feed nut 132 and third lens group holder 11
Although a certain amount of clearance is set in the nut receiving portion 119c of No. 9, the third lens group holder 119 is always biased toward the rear side of the optical axis by the amount of backlash due to the action of the third lens group biasing spring 1230. ing.

Reference numeral 133 is a pressing plate for positioning and holding the yokes 1240, 125, 127, 128 which constitute the step motor with the rear base plate 123, and is fixed to the rear base plate 123 by screws or the like (not shown). There is. In the assembled state, the screw portion 131a of the feed screw 131 is exposed through the opening hole 133a of the holding plate 133, and the magnet 130 is located on the optical axis rear side of the holding plate 133 and the magnet facing pole teeth of the yokes 1240, 125, 127, 128. 1240b, 125b, 127b, 128b is in a state of being located on the inner peripheral portion.

The coil 12 is constructed in the above-described state.
The magnet 130 rotates as a well-known stepping motor by appropriately switching the energization to 6, 129, and as a result, the third group lens holder 119 is moved substantially along the optical axis direction by the action of the feed screw 131 and the nut 132. I am letting you. Reference numeral 134 denotes a fourth lens group holder that holds a fourth lens group (not shown), which is held in a storage portion of the rear base plate 123 on the rear side of the optical axis.

From the shutter base plate 105 described above to the fourth
The components up to the group lens holder 134 constitute a variable aperture unit, a shutter driving unit, a third group lens driving stepping motor unit, and third and fourth group lens units including a fourth group lens.

The photographing system in this embodiment is composed of first to fourth lens groups, and is composed of a fourth lens group zoom lens for moving the respective lens groups to perform zooming. Further, the zoom lens is composed of the fourth lens group and the aperture distance does not change due to zooming.

Next, the zoom drive mechanism of this embodiment will be described. Reference numeral 135 denotes a fixed cylinder that is fixed to the camera body (not shown) with screws or the like and supports the optical system of this embodiment. A female helicoid 135a is formed on the inner peripheral portion of the fixed barrel 135.

FIG. 2 is a schematic view of the fixed barrel 135, as shown in FIG. 1, with its outer surface unfolded at an angle of 0 ° in the horizontal left direction when viewed from the front of the optical axis. 136 is a first differential cam barrel,
The female helicoid 135a of the fixed barrel 135 is provided with a rear male helicoid 136a and a helicoid gear 13 described later.
6b is screwed, and is configured to be movable back and forth while rotating along the helicoid lead in the optical axis direction.

FIG. 3 is a schematic view of the outer surface developed similarly to the fixed barrel 135. As shown in FIG. 3, a rear portion of the first differential cam 136 has a portion 136a in which only a male helicoid 136a is formed, a portion 136b in which gears and helicoids coexist, and a portion 136c in which only gears are present. . Region 136a, 1 where male helicoid exists
Reference numeral 36b has a function of helicoidally coupling with the female helicoid 135a of the fixed barrel 135 and holding the first differential cam barrel 136 so as to be able to move forward and backward while rotating in the optical axis direction. The area 136b where gears are present meshes with the finder drive gear 137 of FIG. 1 and receives a driving force due to the rotation of the first differential cam barrel 136 to drive a finder zoom mechanism (not shown).

Next, a gear escape portion 135b is formed on the inner peripheral portion of the fixed cylinder 135 corresponding to the area (spur gear portion) 136c where only the gear exists so as not to interfere with the gear. A zoom drive gear 138 via a speed reduction mechanism (not shown) meshes with the spur gear portion 136c, and the rotational force causes the first differential cam barrel 136 to rotate and advance and retract in the optical axis direction. At this time, it is possible to expand the helicoid region by coexisting the helicoid in the spur gear portion 136c, but the zoom driving force has a large driving load, and coexistence of the helicoid reduces the meat of the gear portion. Since the strength is lowered and the gear may be broken, it is intentionally formed only by the gear portion 136c.

On the other hand, the coexistence part 13 of the gear and the helicoid
In 6b, the finder zoom drive load applied to the gear portion is smaller than the zoom drive load, and there is no problem in gear strength. Therefore, the coexistence of the helicoid and the gear makes it possible to widen the helicoid region.

In FIG. 1, 139 is the first differential cam barrel 13.
6 is a linear guide cylinder that is integrated with 6 in the optical axis direction and moves forward and backward without rotating.

FIG. 4 is a schematic view of the straight guide cylinder 139 with its outer surface developed as in FIG. In the assembled state, the three protrusions 139a of the straight guide cylinder 139 have three circumferential groove portions 136d (formed on the back side of FIG. 3) formed in the inner peripheral portion of the first differential cam 136. It is supported so as to be slidable relative to each other in three groove portions indicated by broken lines indicating that the The projections 139c at three locations further projecting from the rear end flange portion 139b in the outer peripheral direction are the fixed cylinder 1
35 in the optical axis direction groove portion 135 formed on the inner peripheral portion of 35
It is supported slidably in c.

As a result, when a zoom driving force is applied to the first differential cam barrel 136, when the first differential cam barrel 136 moves forward and backward in the optical axis direction while rotating, the linear guide barrel 139 is provided with the above-mentioned support mechanism. Due to the action, the first differential cam barrel 136 does not rotate integrally with the first differential cam barrel 136, but moves back and forth in the optical axis direction.

Reference numeral 140 is a second differential cam cylinder, and a plurality of cam pins 140a formed at the rear portion of the outer periphery are provided with the straight guide cylinder 13 described above.
It is slidably engaged with and held by a plurality of corresponding inner cam grooves 139d formed on the inner peripheral portion of the groove 9. Reference numeral 141 denotes a second differential cam barrel drive pin, which is fixed to the second differential cam barrel 140 at the time of assembling and has its tip penetrating through the three escape holes 139e of the linear guide barrel 139 to allow the first differential cam barrel 140 to move. Three optical axis direction groove portions 1 formed on the inner peripheral portion of the cam 136
36e is engaged with 36e in a relatively slidable manner.

As a result, the drive pin 141 receives the rotational force of the first differential cam barrel 136 and generates a force for rotating the second differential cam barrel 140 with respect to the linear guide barrel 139. The rotational force causes the second differential cam barrel 140 to move back and forth in the optical axis direction along the inner cam groove 139d of the rectilinear guide barrel 139. As a result, the second differential cam cylinder 14
0 moves further in the optical axis direction with respect to the first differential cam barrel 136 moving in the optical axis direction.

FIG. 5 shows the second differential cam barrel 1 in the same manner as described above.
FIG. 40 is a schematic view of the second differential cam barrel 140 when the outer surface of the first differential lens barrel 140 is expanded.
2, three cam grooves 140b slidably supporting the three cam pins 102e formed on the outer peripheral surface of the rear portion, and three cam pins formed on the rear peripheral surface of the second group lens barrel 104. Three cam grooves 1 for supporting 104b slidably
40c and three cam grooves 140d that slidably support three cam pins 123b formed on the outer peripheral portion of the rear base plate 123 constituting the third and fourth lens units are formed respectively.

When assembled, the rear base plate 123, which is one of the components of the third and fourth lens units, has the cam pin 123b as described above and the cam groove 1 of the second differential cam barrel 140.
The outer peripheral projections 123c at three locations are slidably supported by 40d and slidably supported by the three optical axis direction groove portions 139f formed on the inner circumferential surface of the straight guide cylinder 139. Therefore, it does not rotate along the lift of the cam groove 140d but moves back and forth in the optical axis direction.

At this time, the two cylindrical portions 104c and 104d of the second group lens barrel 104 are slidably supported in the optical axis direction by the notch portions 105d and 105e formed in the outer peripheral portion of the shutter base plate 105. Therefore, as the second differential cam barrel 140 rotates, the second differential cam barrel 140 does not rotate along the lift of the cam groove 140c but moves back and forth in the optical axis direction.

Further, at this time, two ridges 102f, 102 in the optical axis direction are formed on the inner peripheral surface of the first lens barrel 102.
g is the two cylindrical parts 10 of the second group lens barrel 104.
Optical axis direction groove portion 10 formed on outer peripheral portions of 4c and 104d
Since the second differential cam barrel 140 is rotated, the cam groove 14 is supported by the shafts 4e and 104f so as to be slidable in the optical axis direction.
It does not rotate along the lift of 0b but moves back and forth in the optical axis direction.

As described above, in the lens barrel of this embodiment, the first differential cam barrel 136 advances and retreats with respect to the fixed barrel 135 while rotating in the optical axis direction, and similarly the first differential cam barrel 136 is moved. On the other hand, the second differential cam barrel 140 moves forward and backward while rotating in the optical axis direction by the same angle (relative to the fixed barrel). Further, each lens group is further moved in the optical axis direction with respect to the second differential cam barrel 140 without advancing and retracting, so that a zooming operation is performed.

In FIG. 1, reference numerals 142 and 143 denote biasing springs (elastic members), which connect the third and fourth group lens units (shutter unit) and the second group lens barrel (lens holding member) 104 in the optical axis direction. This is for biasing the cam pins 102e, 104b, 123b of each lens group and the cam grooves 140b, 140c, 140d of each lens group to remove the adverse effect due to the lens group tilting due to the rattling.

The bias springs 142, 143 are formed in the notches 105d, 105e of the shutter base plate 105, and the rear side in the optical axis direction is closed by the shutter base plate 105 as the contact surface of the bias springs 142, 143. It is housed in the substantially U-shaped notches 105f and 105g. The cutout portion 105f is set on the blade rotation center side of the tip inner diameter portion 106c of the shutter blade 106 so that the shutter blade 106 does not interfere when the shutter blade 106 is fully closed, and the shutter blade 1 does not interfere when the shutter blade 107 fully opens.
It is set further outside than the outer shape portion 107d of the blade when 07 is fully opened.

Similarly, the setting position of the cutout portion 105g is on the blade rotation center side of the tip inner diameter portion 107c of the shutter blade 107 so that the shutter blade 107 does not interfere when fully closed, and the shutter blade 106 interferes when fully opened. To prevent this, the shutter blade 106 is set further outside than the outer shape portion 106d of the blade when it is fully opened.

FIG. 6 is a schematic view of this state when viewed from the front of the shutter base plate 105.
6 and 107 are shown by a solid line when fully closed, and by a one-dot chain line when fully opened.

In this embodiment, as shown in FIG. 6, notches 105g and 105f are provided on the outer peripheral portion of the shutter unit. Then, bias springs 142, 143 as elastic members are inserted in the notches 105g, 105f. At this time, one ends of the biasing springs 142 and 143 abut on a part of the shutter unit 105, and the other ends thereof are part of the lens holding member 104 (optical axis direction ridges) 10 as described later.
It is in contact with 4g and 104h. The cutout portion 105g,
Reference numeral 105f denotes a pair of shutter blades formed by the outer side of the outer shape portion 107d of the one shutter blade 107 and the inner side 106c of the differential amount outer shape of the other shutter blade 106 when the shutter blades 106 and 107 are fully opened. It is formed so as to be located in the use area Y1.

In this embodiment, by arranging the biasing springs 142 and 143 at the positions as described above, it is possible to effectively use the area that would normally be a dead space. On the other hand, the end faces of the biasing springs 142, 143 on the front side of the optical axis are the optical axis direction ridges 104g formed on the circumferential surfaces of the two cylindrical wall portions 104c, 104d of the second group lens barrel 104. It is in contact with the rear end surface of the optical axis 104h.

As a result, in the assembled state, the second group lens barrel 104 and the third and fourth group lens units are biased in the directions in which they are separated from each other by the action of the biasing springs 142 and 143. 144 is a support shaft for rotatably supporting the zoom drive gear 138 at a predetermined position of the fixed barrel 135.

Reference numeral 145 is a known sliding resistance, which is fixed to the camera body (not shown) with a screw or the like, and its driven projection 145a is engaged with the engaging hole portion 139g of the straight guide cylinder 139. Then, the guide cylinder 13 goes straight by zooming
9 moves in the direction of the optical axis in conjunction with the forward / backward movement, and the stop position of the linear guide cylinder 139 is converted into an electric signal and output.

From the state of the electric signal, the control means provided in the camera body discriminates the focal length of the photographing system at that time, and based on the focal length information and the subject distance information obtained by the known distance measuring means, the stepping is performed. A third lens group holder 119 that holds the third lens group using a motor as a drive source is moved back and forth along the optical axis direction to perform a focusing operation on a subject.

As described above, the photographing system of this embodiment performs the zooming operation by the so-called electronically controlled cam mechanism.

Next, a method of assembling the main parts of the taking lens barrel of this embodiment will be described. First lens barrel 10
2, the second group lens barrel 104, the third and fourth group lens units are respectively movable in the optical axis direction, and the biasing spring 1
42 and 143 are assembled and assembled in the second differential cam barrel 140 along the optical axis direction from the rear in the second differential cam cylinder 140 with the phases of the cam pin and the cam groove aligned.

Next, in this state, the second differential cam barrel 140 is moved from the rear side to the straight guide barrel 139 from behind by the cam pin 140.
The phase of a and the cam groove 139d are matched and assembled along the optical axis direction.

At this time, since the phase state of the second differential cam cylinder drive pin 141 with respect to the straight guide cylinder 139 is at the position indicated by the circle indicated by the alternate long and short dash line in FIG. 4, the drive pin 141 at the center of the three positions in the drawing is shown. Only can be embedded. This is because the remaining two corresponding escape holes 139e are formed so that other pins cannot be incorporated.

Now, the drive pin 1 can be installed in only one place
The pin 41 is rotated counterclockwise in FIG. At this time, the above-mentioned biasing springs 142, 14
By the action of 3, the third and fourth lens units are pushed back to the rear of the optical axis, so the pin is rotated while applying a pressing force in the front direction of the optical axis against this. Then, the second differential cam cylinder 140 is rotated counterclockwise in FIG. 1 with respect to the linear guide cylinder 139 until the remaining two pins can be installed, and then the remaining two drive pins 141 are installed.

When it is rotated to this position, the cam pin 102e of the first lens barrel 102 is moved by the amount of the rotation,
The cam pin 104b of the second group lens barrel 104 and the cam pin 123b formed on the rear base plate 123 are indicated by 3 in FIG.
The biasing springs 142, 143 are drawn from the assembling optical axis direction groove portions 140e into the corresponding cam grooves 140b, 140c, 140d and located between the assembling position and the collapsing position in the figure. The third and fourth lens units will not come off from the second differential cam barrel 140 due to the urging force.

That is, in the assembled position, the drive pin 141
Is used as a clue for pushing the drive pin 141 to rotate the second differential cam cylinder 140 with respect to the linear guide cylinder 139, and carelessly by assembling the remaining pins at a position rotated by a certain amount. Second differential cam cylinder 14
0 rotates with respect to the linear guide cylinder 139, and each lens group is prevented from falling off.

Next, the above-mentioned three second differential cam barrel drive pins 1
Linear guide cylinder 1 in the phase state in which all 41 are incorporated
39 is assembled from the back of the first differential cam barrel 136 along the optical axis direction.

In this way, the first differential cam cylinder 13 is constructed so that the straight guide cylinder 139 can be assembled along the optical axis direction.
Three circumferential groove portions 136d formed on the inner peripheral portion of 6
An escape 136e (in FIG. 3) for incorporation is formed in the corresponding portion of. Since this phase is outside the normal use area after the installation, the three protrusions 139a of the straight guide cylinder 139 will not come off from the circumferential groove portion 136d during normal operation.

In this state, the taking lens barrel is completed by assembling the helixoid phase of the first differential cam barrel 136 with the fixed barrel 135. Since the movement of each part by zooming has already been described, the description thereof will be omitted.

In the present invention, an optical device for forming image information on the photosensitive surface (film surface, CCD surface) is constructed by using the lens barrel described above.

[0066]

As described above, according to the present invention, it is possible to reduce the size of the entire apparatus by appropriately disposing the elastic member for biasing in an area which is not used in the conventional lens barrel. A lens barrel and an optical device using the same, in which the lens holding member can be surely biased in a predetermined direction while the drawing is being carried out, and thereby the lens holding member can be accurately moved during zooming or focusing. Can be achieved.

In particular, according to the present invention, one optical member having the shutter unit and the lens holding member having the above-described structure are provided with a special space by disposing two springs having a small winding diameter in the dead space generated in the shutter blade operating region. Since the positive biasing can be performed without using the camera, it is possible to favorably achieve the two purposes of downsizing the camera and ensuring optical performance.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a first embodiment of the present invention.

FIG. 2 is an external development view of the fixed barrel of FIG.

FIG. 3 is an external development view of the first differential cam shown in FIG.

FIG. 4 is a developed view of the outer surface of the straight guide cylinder of FIG.

5 is a development view of the outer surface of the second differential cam shown in FIG.

FIG. 6 is a front view of the main part of the shutter base plate of FIG.

FIG. 7 is a cross-sectional view of a main part of the lens barrel of Embodiment 1 of the present invention when the lens barrel is collapsed.

FIG. 8 is a cross-sectional view of essential parts of the lens barrel of Embodiment 1 of the present invention at the wide-angle end.

FIG. 9 is a cross-sectional view of essential parts of the lens barrel of Embodiment 1 of the present invention at the telephoto end.

[Explanation of symbols]

 101 first group lens holder 102 first group lens barrel 103 second group lens holder 104 second group lens barrel 105 shutter base plate 106, 107 shutter blade 108 shutter drive magnet 109 magnet cover 110, 111, 112 yoke 113 drive coil 114 Blade Partition Plates 115, 116 Variable Aperture 117 Energizing Spring 118 Variable Aperture Holding Member 119 Third Group Lens Holder 120 Guide Bushing 121 Third Group Guide Bar 122 Third Group Steady Bar 123 Rear Base Plate 124 Third Group Tilt Adjusting Plate 1230 Third group bias spring 1240, 125, 127, 128 Yoke 126, 129 Coil 130 Magnet 131 Third group feed screw 132 Feed nut 133 Holding plate 134 Fourth group lens holder 135 Fixed tube 136 First differential cam cylinder 137 Finder drive gear 138 Zoom drive gear 139 Straight guide cylinder 140 Second differential cam cylinder 141 Second differential cam cylinder drive pin 142,143 Offset spring 144 Spindle 145 Sliding resistance

Claims (4)

[Claims] 1. A lens holding member is fitted into an outer peripheral portion of a shutter unit having at least two shutter blades so as to relatively move in an optical axis direction, and an elastic member is provided in a notch portion provided in the outer peripheral portion of the shutter unit. One end of the elastic member is in contact with a part of the shutter unit and the other end is in contact with a part of the lens holding member so that the shutter unit and the lens holding member are urged relative to each other in the optical axis direction. The notch is located within a shutter blade non-use area formed by the outer side of the outer shape of one shutter blade and the inner side of the operation amount outer shape of the other shutter blade when the shutter blade of the shutter unit is fully opened. A lens barrel characterized in that 2. The lens barrel according to claim 1, wherein at least two elastic members are provided. 3. The lens barrel according to claim 1, wherein at least two shutter blade non-use regions are formed with an optical axis interposed therebetween. 4. An optical device, wherein image information is formed on a predetermined surface by using the lens barrel according to claim 1. Description: