JP2856557B2 - Variable focal length device and camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus of a zoom lens or the like.
Distance is relates to an improvement of a variable device.

[0002]

2. Description of the Related Art A conventional zoom lens mechanism includes a plurality of lens units.
Displacement units along different cam grooves
This changes the focal length .

[0003]

However, in the case of the variable focal length mechanism having such a configuration, there is a problem that the number of cam grooves must be provided as many as the number of lens units, and the configuration becomes large.

[0004]

[0005]

[0006]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a variable focal length device and a camera which can be downsized.

[0008]

In order to achieve the above object, a variable focal length apparatus and a camera according to the present invention include a first lens unit, a second lens unit, and the second lens unit.
A motor for moving the first lens unit with respect to the first lens unit, a moving unit for integrally moving the first and second lens units and the motor in the optical axis direction, and the moving unit. Determining means for determining a stop position of the first lens unit; and determining for determining a moving position of the second lens unit moved by the motor with respect to the first lens unit according to a result of the determination by the determining means. Means.

[0009]

FIG. 1 is an exploded perspective view showing a taking lens barrel of a camera with a zoom lens according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a first lens barrel for holding a first lens L1 shown in FIG. 3 at a tip 1a, and a second lens barrel 2 is located at the inner diameter of the lens barrel and rotatably fitted thereto. A group cam ring 3 holds the second group lens L2 shown in FIG. 3 and a shutter base plate having a known shutter unit, 4 denotes a third group holder for holding the third group lens L3, and 5 denotes the first lens. The first group cam ring 6, which defines the position of the group lens L1 in the direction of the photographing optical axis, has the first group cam ring 5 rotatably fitted to the inner diameter portion thereof, and the first group lens barrel 1 forms the photographing light. The notch groove 6a is a straight guide provided on its inner surface so as to be able to move straight only in the axial direction. In the above-described configuration, an internal gear 5d (see FIG. 6) is disposed at the inner rear end 5a of the cam ring 5, and the gear 7 is engaged with the internal gear 5d.
A gear 8 receiving power from a known drive source (not shown) is engaged. The cam ring 5 is rotatably held on the inner peripheral surface of the rectilinear guide 6, and its movement in the optical axis direction is caused by the implantation pin 9 being engaged with the elongated hole 6 b of the rectilinear guide 6 provided in the circumferential direction. Therefore, the movement is regulated.

An implanting pin 10 similar to the implanting pin 9 is implanted at the rear of the first lens unit barrel 1. The pin 10 is slidable with respect to the cam groove 5b of the cam ring 5 and also slidable with the notch groove 6a of the linear guide 6.

When the gear 8 starts rotating by receiving power from a drive source (not shown), the gear 7 rotates, and this rotational force is transmitted to the internal gear 5d of the cam ring 5, and the cam ring 5 rotates.
Starts spinning. Further, since the position of the pin 10 implanted in the first lens barrel 1 is regulated by the cam groove 5b and the notch groove 6a, the displacement of the cam groove 5b due to the rotation of the cam ring 5 in the optical axis direction. By driving the lens barrel 1 by the distance in the optical axis direction, the zooming operation of the first lens unit L1 can be performed.

Next, the zooming operation of the second group lens L2 will be described. The second group cam ring 2 is rotatably held on the inner peripheral surface of the first group lens barrel 1, and a pin 11 implanted at the rear end 2 a has a length in the circumferential direction of the first group lens barrel 1. While being slidably held in the hole 1b,
The cam ring 5 is also slidable with respect to the elongated hole 5c in the optical axis direction. Now, as described above, when the cam ring 5 starts rotating, the first lens unit barrel 1 moves along the optical axis.
As a result, the first lens unit barrel 1 is regulated by the elongated hole 1b, and moves together with the first lens unit lens barrel 1 in the optical axis direction. Further, the planting pin 11 is a long hole 5c of the cam ring 5.
The second group cam ring 2 is not used for rotation of the cam ring 5 because the first group lens barrel 1
Together with the cam ring 5 and rotate at the same angle as the cam ring 5.

The first group lens barrel 1 has two second group guide bars 12 and 13 fixed parallel to the optical axis in the inside thereof, and one of the guide bars 12 is compressed on the outer periphery thereof. It has a spring 14 and is slidably fitted in the hole 3a of the shutter base plate 3 to generate a force for urging the shutter base plate 3 backward (in the direction of arrow A in FIG. 1) of the optical axis. The other guide bar 13 engages with the notch groove 3b of the shutter base plate 3 to prevent the base plate 3 from rotating around the fitting hole 3a, so that the base plate 3 can only move in the longitudinal direction of the optical axis. It becomes possible. An implantation pin 3c is further fixed to the shutter base plate 3, and the pin 3c engages with the cam portion 2b of the second group cam ring 2. Accordingly, the position of the shutter base plate 3 in the optical axis direction is controlled by the cam portion 2b of the second group cam ring 2 which is engaged with the planting pin 3c while being biased backward by the optical axis by the compression spring 14. Is performed. Accordingly, along with the zooming of the first lens unit L1 by the rotation of the cam ring 5, the position of the shutter base plate 3 holding the second lens unit L2 in the optical axis direction is defined, and the zooming operation of the second lens unit L2 occurs. Further, as described above, the shutter base plate 3 can move in the forward direction of the optical axis against the force of the compression spring 14, so that when the shutter base plate 3 descends, it is pressed from the rear side of the optical axis, so that the first base plate 3 is pressed. Group and second group lens L1, L2
Can be narrowed.

Next, the operation of the third lens unit L3 will be described. Third group guide bars 15 and 16 are fixed to the third group holder 4 holding the third group lens L3 so as to be substantially symmetric with respect to the optical axis so as to be parallel to the optical axis.

One guide bar 15 is provided with a compression spring 17 on its outer periphery, is slidably held in a fitting hole 3c 'of the shutter base plate 3, and the other guide bar 16 is a notch of the base plate 3. By engaging with the groove 3d, the holder 4 can be moved only in the optical axis direction. Further, the holder 4 is provided with a male helicoid screw 18 implanted in parallel with the optical axis. The helicoid 18 engages with the female helicoid gear 19, and the rotation of the gear 19 causes
The third group holder 4 can move in the optical axis direction.

Reference numeral 190 denotes a known stepping motor unit having a permanent magnet rotor 20 polarized in four poles in the circumferential direction. The yokes 21 and 23 together with the bobbin 25 form one magnetic path, and the yokes 22 and 24 together with the bobbin 26 form another magnetic path. FIG. 2 is a front view showing the configuration of the stepping motor.

Reference numeral 27 denotes a magnet cover having a fitting hole 27a for rotatably positioning the upper end of a central shaft 28 fixed to the permanent magnet rotor 20. The other end 28a of the center shaft 28 is rotatably held by a through hole 3e provided in the shutter base plate 3 and is supported between the center cover 28 and the magnet cover 27. 28a is the shutter base plate 3
Pinion 2 for projecting to the back side of the
9 is fixed to the tip.

In the stepping motor 190 having the above structure, the coils wound around the bobbins 25 and 26 are energized, the yokes 21 to 24 are energized, and the phase of the energization is appropriately switched to rotate the permanent magnet rotor 20. Then, the output is transmitted to the pinion 29. Pinion 2
When 0 starts rotating, the reduction gear train 30 sequentially rotates, the output of which is transmitted to the female helicoid gear 19, and the gear 19 starts rotating. By this rotation, the male helicoid 18 is driven in the optical axis direction, and as a result, the third group holder 4 is moved in the optical axis direction, that is, zooming is performed.

In this embodiment, since the focus correction, that is, AF (autofocus) is performed by a rear focus type photographing lens system performed by the third lens group L3, the third lens group L3 is the same as that described above. In addition to the zooming operation, lens position control for focus correction is also performed. However, the driving principle is the same as in the case described above, and the description thereof will be omitted. Although not described in the above description, the compression spring 17 biases the third group holder 4 rearward of the optical axis to offset the backlash of the male helicoid 18, the female helicoid gear 19, and the reduction gear train 30. Have a function. The actual zooming and focusing will be described later in detail. Further, the shutter base plate 3 includes, for example, a known shutter drive unit 31 previously proposed by the present applicant, and a pair of shutter blades 32 and 33 held between the blade holder 34 and the base plate 3. And has a function of exposing a photographic film by driving the camera.

A gear 35 is attached to the rear end of the linear guide, and the gear 7 is attached to the projection 35a, and the gear 8 is attached to the projection 35.
b is a helicoid plate which is rotatably held on each of the female helicoid gears 36 and 37 so that the helicoid parts 36a and 37a of the helicoid gears 36 and 37 engage with the female helicoid parts of the female helicoid parts 35c and 35d, respectively. It is clear from the figure that the female siliconoid portions 35c and 35d are located inside the outer diameter of the lens barrel unit.

The photographing lens barrel unit is formed by the components including the helicoid plate 35 as described above.

Next, the retracting operation of the taking lens barrel unit will be described.

FIG. 6 is a longitudinal sectional view of a main part, taken along a plane including the photographing optical axis of the camera in FIG. The lower side of the optical axis center is a so-called collapsed state in which the lens barrel unit is housed inside the camera body 39, while the upper side of the optical axis is a state in which the lens barrel unit is protruded from the retracted position. It represents.

Numerals 36 and 37 are rotatably supported on shafts 39a and 39b provided at the bottom of the camera body, respectively, and their movements in the optical axis direction are controlled by the camera body 39.
Presser plate 4 attached with a set screw (not shown)
The helicoid gear is regulated by the helicoid gears 1, 42. The male helicoid parts 36a, 37a of the gears 36, 37 are female helicoid parts 35c, 35d of the aforementioned helicoid plate 35.
(See FIG. 1), and the lens barrel unit is retracted and extended.

Numeral 40 designates an internal gear at its inner diameter, which engages with the helicoid gears 36, 37, and an outer periphery which engages with a gear 48 for transmitting an output from a drive source (not shown). Internal and external gears having external gears. When the gear 48 forming the driving member of the lens barrel unit starts rotating by receiving an output from a driving source (not shown) with the above-described component configuration, the internal and external gears 40 rotate around the photographing optical axis. Then, the helicoid gears 36 and 37 engaged with the internal teeth of the gears start rotating in the same direction and at the same angle, so that an even force is exerted on the female siliconoid plate 35 and the lens barrel unit is smoothly retracted or hollowed out. It is possible.

Numeral 38 denotes a fixed lens barrel fixed to the camera body 39. The lens barrel unit is held in the opening hole 39a of the camera body 39 and the opening hole 38a of the fixed lens barrel 38, and the optical axis is fixed. It can be moved in the front-back direction. At this time, since the main body 39 and the fixed lens barrel 38 are provided with slidable fitting grooves at positions corresponding to the rotation stopping projections 6f of the rectilinear guide 6, the lens barrel unit does not rotate.

In FIG. 1, reference numeral 43 denotes a bayonet ring.
As shown in FIG.
As shown in FIG. 7, the above-mentioned straight guide 6 comprises three projections 6c, 6d, 6e and a rotation stopping projection 6f provided at its rear end.
Further, the opening shape including the zoom drive gear 8 can be passed through the inside thereof. Reference numerals 44 to 46 denote bayonet holders attached to the camera body 39 and disposed in front of the bayonet ring 43 along the optical axis. A piece is extended. A lens barrel holding member is formed by the bayonet ring and the bayonet holder. In hollowing out from the retracted position, first, the gear 43 rotates in response to an output from a drive source (not shown), and accordingly, the internal and external gears 40 rotate, and the helicoid gear 3 is rotated.
6, 37 start rotating in the same direction and at the same angle. Gear 3
The rotation of the female helicoid plate 35 pushes the female helicoid plate 35 forward of the optical axis, so that the lens barrel unit is guided by the opening hole 39c of the camera body 39 and the opening hole 38a 'of the fixed lens barrel 38, and the rotation stopper is stopped. The lens barrel unit is drawn out while its rotation is restricted by the projection 6f. At this time, due to the action of the compression spring 14 provided on the outer peripheral portion of the guide bar 12 as described above, the distance between the first group lens and the second group lens gradually increases, and the female helicoid plate 35 After the protruding pin 35e abuts, the abutment between the third group holder 4 and the upright bend 41a of the holding plate 41, which has been abutted up to that point, is released, and the distance between the first group lens L1 and the second group lens L2 is released. The lens barrel unit is drawn out with the constant.

When the extension of the lens barrel unit comes to an end, the lens barrel unit reaches a position where it passes through the bayonet ring.

When this state is reached, the large diameter portion 6g formed at the rear portion of the linear guide 6 becomes the opening 38a of the fixed lens barrel 38.
Is held without backlash in the inner diameter portion of. FIG. 7 shows a front view of a main part of the straight guide 6, the bayonet ring 43, and the bayonet retainers 44, 45, 46 in this state.

When the power supply is cut off to draw out the lens barrel unit, the unit stops in the above-described state. At this time, the bayonet retainers 44, 45, 46
Although it should generate a force to return the projections 6c, 6d, and 6e of the cage to the rear of the optical axis, the bayonet ring 4
3 has a step 43a as shown in FIG.
Since there are 43b and 43c, the bayonet retainer is locked at this portion, and the lens barrel unit has a position where its rear end has passed through the bayonet ring, that is, as shown in FIG.
The bayonet ring 43 stops in a state in which the rear end of the unit is located further in front of the paper than the front 43d of the paper.

In this state, power from a drive source (not shown) is transmitted to the gear 47, and the gear 47 starts rotating clockwise. The bayonet ring 43 not subject to the above-described movement starts to rotate counterclockwise. The rotation of the bayonet ring also rotates the steps 43a, 43b, 43c, which have been locked by the spring forces of the bayonet holders 44, 45, 46, so that the locking is released, and then the bayonet holders 44, 45, 46 is a projection 6c, 6 of the linear guide 6.
It starts to generate a force that pushes d and 6e backward of the optical axis. However, at this time, since the bayonet ring has already been rotated by a certain angle, the projections 6c, 6d, 6e of the rectilinear guide are pressed against the bayonet rings 43e, 43f, 43g by the pressing.

When the rotation of the bayonet ring continues,
This time, the protruding portions 6 of the linear guide 6 are formed by the cut-and-raised cams 43h, 43i, 43j provided on the bayonet ring.
The rear end surfaces of c, 6d, and 6e are pushed by the cam, and the unit is further drawn forward in the optical axis against the pushing.

Thereafter, the projections 6c, 6d, 6e are connected to the cam surfaces 43h, 43i, 43j of the bayonet ring 43.
Plane part 43 provided on the extension of
When the vehicle rides on the k, 43l, 43m section, the power from the drive source is shut off.

FIG. 8 is a front view of a main part in a state where the above-mentioned movement is completed. In this state, the lens barrel unit completes the extension from the retracted position, and the photographing lens barrel unit is firmly engaged and held at the photographing standby position. The state of the taking lens at this time is shown above the optical axis in FIG.

FIGS. 9 and 10 illustrate a state in which the gear 8 for rotating the cam ring 5 and the gear 50 for rotating by receiving power from a drive source (not shown) are connected by the above-mentioned retracting operation from the retracted position. It is principal part sectional drawing of.
FIG. 9 shows a state in which the gears 8 and 50 are being pulled out of the retracted state, and the gears 8 and 50 are not yet connected in this state. After that, when the lens barrel unit is further drawn out and the gears 8 and 50 shown in FIG. 10 are connected, the lens barrel unit is set in a state where the teeth of the gear 8 and the gear 50 do not interfere with each other. When the gear 50 is pulled out (that is, the gear 8 and the gear 48 are properly meshed), the gear 50 stands by at the position shown by the solid line under the urging force of the coil spring 49 and is connected to the gear 8.

However, when the teeth of the gear 8 and the teeth of the gear 50 interfere with each other due to the hollowing out of the lens barrel unit (that is, the teeth of the gears 8 and 50 collide with each other), the gear 5
Numeral 0 retreats to a position shown by a chain line in FIG. 10 against the urging force of the coil spring 49 while being rotatably held by a shaft 39e protruding from the camera body 39. Gear 5
The drive force from the drive source (not shown) is transmitted even in the state in which the gear 50 is retracted (for example, the tooth thickness is adjusted so that the gear on the drive side (not shown) can mesh with the gear 50 even in the retracted position. When the gear 50 rotates to a position where the gear 50 can engage with the gear 8 under the power from the drive source, the gear 50 slides to a position shown by a solid line in FIG. The connection with the gear 8 is performed.

In the state where the hollowing out from the collapsing is completed,
The first, second and third lens groups are not in the photographing position, and thereafter the camera rotates the cam ring 5 by a certain angle by the aforementioned driving means. Then, the first lens unit is drawn out to the WIDE shooting position shown below the optical axis in FIG. Accordingly, the distance between the first lens unit and the second lens unit is further increased by the action of the compression spring 14, and
The group lens has the planting pin 3c of the shutter base plate 3 abutting on the cam surface 2b of the second group cam ring 2, and is held at the WIDE shooting position similarly to the first group lens. A cross section of the main part of the taking lens unit at this time is shown below the optical axis in FIG.
The upper side of the optical axis is a state in which the hollowing out of the lens barrel unit has been completed, and is the same as the upper side of the optical axis in FIG.

After rotating the cam ring 5 to the above state, the third lens group is driven to an appropriate position by the stepping motor 190 as described above, and the photographing lens system completes the preparation for WIDE photographing. The cross section of the main part of the taking lens unit at this time is shown on the upper side of the optical axis in FIG. The lower side shows a state in which the photographing lens system is arranged at the TELE position by forward zooming, but the zooming operation has been described in detail above, and a description thereof will be omitted.

When the lens barrel unit is retracted from the retracted state, only the movement of each part in the above-described retracting operation from the retracted state is reversed.
The details are omitted.

The mechanical structure and operation of the zoom lens have been described above. Hereinafter, the lens position control of the first group lens, the second group lens, and the third group lens will be described.

The zoom lens according to the present embodiment does not continuously change the focal length from the wide-angle end to the telephoto end in a stepless manner. After performing the position control of the first and second lens units, the third lens unit is extended to a predetermined position, and the position control of the focal length is completed. Needs to detect the exact position of the first and second lens units.

FIGS. 3 to 5 show an embodiment of the lens position detecting device.

Reference numeral 53 denotes a prism extending in the optical axis direction. A slit plate 53a shown in FIG. 5 is provided on one side of the prism, and is fixed to the first lens unit barrel 1. Reference numeral 52 denotes, for example, a photodetector attached to the shutter base plate 3 and moved integrally with the second lens group. As shown in FIG. A light receiving element 52b opposed to the slit plate 53a provided on the emission surface side. The infrared light emitted by the light projecting element 52a is reflected by the reflection surface 53b of the prism 53, and only the light that has passed through the slit 53c of the slit plate 53a is projected on the light receiving element 52b as slit light.

The slit plate 53a is, as shown in FIG.
Two rows (L1 row, L2 row) of slits are formed in parallel,
The light receiving element section 52b is also provided with two light receiving elements 52c and 52d corresponding to the slits in the L1 and L2 rows. These light receiving elements 52c, 52d
Is designed such that a position detection sensor (PSD) can detect the projection position of the slit light.

The slit plate 53a is, as shown in FIG.
The slits 53c of the L1 row and the L2 row are formed in a direction orthogonal to the optical axis (lens barrel), and the pitches of the slits arranged along the optical axis direction of the L1 row are equal (pitch P
1) The distance D between the slits 53c-1 and 53c-2 formed and located at both ends in the optical axis direction of the L1 row is equal to the maximum value of the relative movement amount of the first lens group and the second lens group in the present embodiment. doing. The slit interval (pitch P1) is
The length of the light receiving surface of the light receiving element 52d in the optical axis direction is longer than the length 1 so that the slit light passing through the adjacent slit does not simultaneously enter the light receiving element 52d.

On the other hand, there is a shift with respect to the slit L1 in the L2 row, and by reading the shift amount from the output difference between the light receiving elements 53c and 53d, the lens positions of the first lens group and the second lens group (zoom position) ) Can be determined. Center slit 53c-4 in slit row L1
Of the slit 53c-3 of the slit row L2 corresponding to the above, the shift amount is 0, and the slits of the L2 row in the region indicated by S other than the slits at both ends are the same as the slits of the corresponding L1 row. Having Z1 and L1
They are arranged so that the shift directions are alternately reversed with respect to the adjacent slits in the row. Further, with respect to the slits 53c-1 and 53c-2 at both ends of the L1 row, the slits of the L2 row are arranged with a shift Z2 satisfying Z1 <Z2.

FIG. 19 shows the light receiving elements 53c and 53d.
FIG. 7 is a block diagram of a control device that controls a stepping motor 190 that drives the third lens group based on detection information from a position detection sensor having a function of moving the third lens group to a predetermined position. 100 is a light receiving element 52c,
An amplifier 101 amplifies the detection signal from 52d. A microcomputer 101 performs A / D conversion of the amplified detection signal of the light receiving element, performs an arithmetic process described later from the value, and performs stepping through the stepping motor drive circuit 102. Power is supplied to the coils 25 'and 26' of the motor 190. The microcomputer 101 is also used as control means for performing a predetermined operation to drive the first and second lens groups, and performs the following processing.

First, a description will be given of lens position control when zooming is performed from the WIDE to the TELE direction. FIG.
The positional relationship between the slit 53a and the light receiving elements 52c and 52d shown in FIG. 3 shows the upper WIDE state in FIG. When the photographer operates a zoom switch (not shown) of the camera to perform a zoom operation toward the long focal length, the microcomputer 101 determines the state of the zoom switch and turns on the infrared light emitting element 52a. At the same time, the output of the light receiving element 52d for the slit L1 row is started to be determined. On the other hand, receiving power from a drive source (not shown), FIG.
When the gear 8 starts rotating, the zoom operation of the taking lens system is started as described above, and the first lens unit barrel 1
The second group cam ring 2 is drawn out to the ELE side.
An operation occurs such that the distance between the first lens unit and the second lens unit is reduced by the action of (1). In accordance with this movement, in the position detecting device in FIG. 5, the slit plate (that is, the prism 53) 53a starts to be displaced toward the camera body with respect to the light receiving elements 52c and 52d. At this time, waveforms as shown in FIGS. 13 and 14 are output from the output terminal 52f of the light receiving element 52d and the output terminal 52e of the element 52c. FIG. 13 shows the output terminal 5
FIG. 14 shows an output terminal 52f.
e is a signal output from e. FIG. 15 shows the comparator output of the output from the output terminal 52f and the judgment level set to about half of the maximum value of the output value. Now, when the photographer keeps turning on the zoom switch, the comparator output shown in FIG. 15 outputs a rising signal in order of C ₂ , C ₃ ,. In this embodiment, the number of outputs is thirteen as is apparent from the number of slits in the slit row L1 in FIG. When middle photographer of the zoom operation is off the zoom switch, the lens position control device of the camera continues to zooming operation until the comparator output in Figure 15 outputs the next rising signal C _n signals, the rising signal C _n When the microcomputer determines, the power supply to the power source is cut off and the zooming operation ends. While camera zoom operation in this description are feeding from WIDE to TELE side, when the operation of pulling from TELE to WIDE is to remove backlash mechanism, has passed once stop position to a target, for example a C ₃ after detecting the next signal C _2, switch to energization of the feeding direction to the TELE side, performs control method to stop at C _3.
The movement of the lens barrel at this time is schematically represented by K in FIG. That is, in this embodiment, the focal length regardless zoom direction will take the zoom position 13 shown in C ₁ -C _13.

In this embodiment, in the slit shown in FIG. 5, the slits 53C-1, 53c-2, 53c in the L1 row are used.
-4, the corresponding L2 row slits 53c-5, 53c-6, and 53c-3 have different shift amounts and shift directions.
By reading the difference and the deviation direction from d, it is possible to absolutely detect the position of the slit, in other words, the position of the zoom position. However, regarding the slits located in the S region in FIG. 5, the deviation directions are formed alternately, but since the deviation amount is constant, it is impossible to absolutely detect the zoom position position alone. It is possible.

On the other hand, the movement of the lens barrel is started at the WIDE end, ie,
In terms of a slit, 53c-2 and 53C-6 are located at the light receiving elements 52d and 52c, respectively, and the absolute value of this position is read, and the position is stored in the microcomputer. Zooming operation after this, for example, when the stopped picking up signals of C ₄ shown in FIG. 15, since the camera which counts the number of pulse signals C _n generated by zooming, recognizing the zoom position position Can be. In this state, prior to photographing, control is performed to read the corresponding slit in the L2 row and confirm the direction of the shift. Further, the photographing lens barrel, by an external force, the case where the zoom position is shifted even to the telephoto side 1 position (C ₅ in this embodiment)
If a friction mechanism is arranged on a known compression spring or the like in the middle of the zoom power transmission mechanism so as not to shift as described above, it is possible to determine the position of the adjacent one of the slits, so that the position of the slit will not be mistaken. . At this time, the gear train of the zoom power transmission mechanism is arranged such that the zoom driving method is always terminated by energizing in the direction of extending to the telephoto side as described above, so that the direction in which the lens barrel is returned, that is, the direction 16a in the drawing Does not move due to the action of the friction spring because the backlash is blocked. This is what C
Even if Hikkomeyo to WIDE side photographing lens barrel stopped at ₄ against the camera front direction, that even trying to move to the zoom position corresponding to the C ₃ pulses,
It means not moving. This is because of the barrel by backlash or the like of the backlash or the like, even when moved to the zoom position corresponding to C ₅ pulses telephoto side, never it to ensure that it is not a zoom position corresponding to the C ₃ pulses is there.

[0052] Further, the lens barrel in backlash exceeds the C ₅ pulses corresponding position by the backlash or the like, to stop the zoom position a position corresponding to C ₆ pulses (i.e. misread the C ₄ corresponding positions) that as there is no looseness By arranging the friction spring at a position where the amount becomes large, it is ensured that there is no misreading when the zoom position is shifted due to an external force or the like. In addition, the deviation from the slit in the L1 row is Z1 in FIG.
The difference between Z2 and Z2 is made as large as possible within the limited range of the sensor length m by reducing the number of shifts required for zoom position discrimination so as to prevent erroneous reading of the sensor itself. I have.

FIG. 17 is a diagram showing the amount of protrusion of each lens group by zooming. The position shown by the broken line in the figure indicates the position when the infrared slit light transmitted through the slit in the L1 row in FIG. 5 reaches the center of the light receiving element 52d. This because the determination level shown in FIG. 13 is adjusted to half of its output, to match the timing of leaving the C _n pulses of Figure 15. Now, when the completion of the zooming operation by detecting the C ₄ pulses, the position indicated by the two-dot chain line, that is L1
It is assumed that the light receiving element 52d stops at a position slightly shifted from the center of the light receiving element 52d corresponding to the row. At this time, the third lens unit assumes that the photographing lens barrel has the position indicated by the broken line (C ₄ ) in FIG. 17, that is, the slit light is located at the center of the light receiving element 52d.
Only x _1, a state of being moved toward the camera body by a stepping motor. FIG. 18 shows the relationship between the subject distance and the movement amount Δx of the third lens unit. In the figure, Δx ₁ is the focus when stopped at the center of the zoom position at the interval of the reference 2-3 group lens as shown in FIG.
Corresponding to the position. With this amount, the zoom position C ₁
It is a function of the C _13.

ΔF is a movement amount corresponding to the reciprocal of the subject distance D, and is a function of 1 / D and zoom positions C _{1 to} C ₁₃ .

Δx ₂ is a correction amount of the moving amount corresponding to the stop position deviation Δz _p , Δz _p and zoom positions C _{1 to} C
₁₃ functions.

Therefore, the total movement amount Δx of the third lens unit
Is given by Δx = Δx ₁ (C _n ) + ΔF (C _n 1 / D) + Δx ₂ (C _n , ΔZ _p ), and is processed by the microcomputer 101.

Hereinafter, a specific calculation procedure will be described with reference to a flowchart shown in FIG. When the first stroke switch SW1 is turned on by the pressing of a shutter button (not shown), the microcomputer 101 calculates the shift amount [Delta] Z _p from the center of the stop position of the zoom from the output of the light receiving element 52c, 52 d. Also, since I know the zoom position,
The reference movement amount Δx ₁ of the third lens group corresponding to the zoom position is read from the ROM of the microcomputer 101, and
This is defined as Δx.

Next, the distance to the subject is measured by a known distance measuring means, and the microcomputer 101 determines the distance based on the 1 / D information.
The information of ΔF is read from the ROM of (4), and (Δx + ΔF) is
x. Further, information of Δx ₂ is read from the ROM of the microcomputer 101 based on the deviation amount ΔZ _p information, and Δx + Δ
the x ₂ and Δx. By this processing, Δx = Δx ₁ + ΔF
+ Δx ₂ , which means that the movement amount of the third lens unit has been calculated.

Further, when the second release switch SW2 is turned on by pressing the shutter button, the third lens group is moved by the stepping motor by an amount based on Δx, and after the shutter opening / closing operation and the film winding operation are completed, The third lens unit returns to the position of Δx ₁ (that is, the original initial position).

In the embodiment described above, the slits in row L2 and the light receiving element 52c in FIG.
Similar effects can be obtained by performing the zoom position determination using a flexible substrate for determining the zoom position as shown in FIG. In other words, the zoom position may be determined inside the lens barrel.

FIG. 21 shows a known zoom position detecting flexible substrate 18A having a pattern for determining a zoom position, for example, 18a formed on the surface thereof.
The patterns in the 18b to 18e columns are the patterns 18g to 18g, respectively.
In order to output the conduction state to 18j, as shown in FIG. 22, conduction is provided in the back surface pattern and through hole 18l. The pattern 18f is a ground pattern that is conducted to the pattern 18k as described above and drops the pattern of the preceding 18b to 18e columns to the ground level. FIG. 23 shows a rear view of a main part in a state where the flexible 18A is incorporated in the lens barrel. The zoom position detecting flexible 18A is fixed to a counterbore 6g formed on the inner diameter of the linear guide 6 by a known means such as a double-sided tape, and the outer periphery 5e of the cam ring 5 rotates integrally with the cam ring. A coil spring made of, for example, a conductive material is used to slide on the pattern surface of the flexible 18A and determine the amount of rotation of the cam ring 5 by the conduction state of the corresponding zoom position detecting flexible pattern.

The flexible signal extracting portion 18m is connected to the microcomputer of the camera main body by a known means after being pulled out from the inner diameter counterbore portion 6h of the straight guide in FIG. With such a configuration, the zoom position can be adjusted by the pattern of the flexible 18A and the coil spring 5e.
The object of the present invention can be achieved by determining the position of the lens barrel, that is, the correct focal length, by using the slit and the light receiving element, in addition to the determination based on the conduction state of. (Correspondence between Invention and Embodiment) In the embodiment described above, the second group lens L2 is stepped into the "first lens unit" of the present invention, and the third group lens L3 is stepped into the "second lens unit". Motor 19
0 is “motor” and the second group cam ring 2 is “moving means”
The photodetector 52 and the prism 53 serve as “determining means”, the microcomputer 101 serves as “determining means”, “control means” and “starting means”, and the first lens unit L1 serves as a “third lens unit”. The compression spring 14 corresponds to an "elastic member" according to claim 13, the compression spring 17 corresponds to an "elastic member" according to claim 14, and the shutter base plate 3 corresponds to a "shutter unit".

[0063]

As described above, according to the present invention, it is possible to provide a variable focal length device and a camera capable of achieving miniaturization.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a lens barrel of a camera with a zoom lens according to an embodiment of the present invention.

FIG. 2 is a front view of a stepping motor for driving a third lens group in FIG. 1;

FIG. 3 is a sectional view of the lens barrel shown in FIG. 1;

FIG. 4 is a schematic diagram of a lens position detecting device of the camera shown in FIG. 1;

5 is a plan view of a slit plate of the camera shown in FIG.

FIG. 6 is a sectional view of the camera shown in FIG. 1;

FIG. 7 is a diagram showing a relationship between a bayonet ring and a first group cam ring in FIG. 1;

FIG. 8 is a diagram showing a relationship between the bayonet ring and the first group cam ring in FIG. 1;

FIG. 9 is a view for explaining a power connection state of zooming of the camera shown in FIG. 1;

FIG. 10 is a view for explaining a power connection state of zooming of the camera shown in FIG. 1;

FIG. 11 is a sectional view of the lens barrel shown in FIG. 1;

FIG. 12 is a sectional view of the lens barrel shown in FIG. 1;

FIG. 13 is an output waveform diagram of the lens position detecting device of the camera shown in FIG. 1;

FIG. 14 is an output waveform diagram of the lens position detecting device of the camera shown in FIG. 1;

FIG. 15 is a waveform chart in which information from a lens position detecting device of the camera shown in FIG. 1 is compared and output by a comparison circuit.

FIG. 16 is a view for explaining backlash of gears of the camera shown in FIG. 1;

FIG. 17 is a diagram showing a positional relationship between the camera shown in FIG. 1 and a zoom position lens.

FIG. 18 is a diagram illustrating a relationship between an extension amount of a third lens unit of the camera shown in FIG. 1 and a subject distance;

FIG. 19 is a block diagram of a lens control device of the camera shown in FIG. 1;

20 is a flowchart showing a lens position control operation of the camera shown in FIG.

FIG. 21 is a plan view of a flexible substrate showing another embodiment of the present invention.

FIG. 22 is a diagram showing a back surface of the flexible substrate in FIG. 21;

FIG. 23 is a diagram showing a state in which the flexible substrate shown in FIG. 21 is incorporated in a lens barrel.

[Explanation of symbols]

1: 1st lens barrel 2: 2nd group cam ring 3: Shutter base plate 4: 3rd group holder 5: Cam ring 6: Straight running guide 7, 8: Gear 9, 10, 1
1: Planting pins 12, 13: 2nd group guide bar 14, 17:
Compression spring 15, 16: Group 3 guide bar 18: Male helicoid 19 Female helicoid gear 20: Permanent magnet rotor 21, 22, 23, 24: Yoke 25, 26: Bobbin 27: Magnet cover 28: Central axis 29: Pinion 30: Reduction gear train 31: Shutter drive unit 32, 33: Shutter blade 34: Blade holder 35: Female siliconoid plate 36, 37:
Helicoid gear 39: Main body 40: Internal and external gears 41, 42: Holding plate 43: Bayonet ring 44, 45, 46: Bayonet holding 47, 48: Gear 49: Coil spring 190: Stepping motor unit 18A: Zoom position detection flexible 51: Coil Spring 52: Photodetector 52a: Infrared light emitting element 52b: Infrared light receiving element 53: Prism 53a: Slit plate 101: Microcomputer L1: First group lens L2: Second group lens L3: Third group lens

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02B 7/08 G02B 7/09 G02B 7/10 G02B 15/16 G02B 15/22

Claims (23)

(57) [Claims] A first lens unit, a second lens unit, and the second lens unit, the first lens unit being connected to the first lens unit;
A motor that moves with respect to the lens unit;
The second lens unit and the motor are integrally integrated in the optical axis direction.
Moving means for moving the
A stop position of the first lens unit to be stopped is determined.
Determining means for determining
The second lens unit moved by the motor;
The position of the unit relative to the first lens unit.
A variable focal length device. 2. The moving means for changing a focal length.
2. A focal length according to claim 1, wherein the focal length is operative.
Transformers . 3. The motor is operated for changing a focal length.
3. The focal length according to claim 1, wherein the focal length is used.
Variable separation device . 4. The motor acts for focus adjustment.
The focal length according to claim 1 or 2,
Transformers . 5. The motor according to claim 1, wherein said motor has a focus adjustment and a focal length change.
3. The method according to claim 1, wherein
The variable focal length device as described in the above . 6. The first and second moving means by the moving means.
When the lens unit is moved, the first,
A third lens whose distance from the second lens unit changes
6. The method according to claim 1, further comprising a unit.
A variable focal length device according to any of the preceding claims . 7. A motor for operating a shutter release member.
Characterized by having control means to act in response to the crop
The variable focal length apparatus according to any one of claims 1 to 6.
Place . 8. A motor for operating a shutter release member.
Acts to adjust focus and change focal length in response to crop
7. A control device for controlling the operation of a vehicle.
The variable focal length device according to any one of the above . 9. The shutter release member according to claim 9, wherein:
For focus adjustment and focal length change in response to the operation of
請that the amount of the action of the serial motor, wherein the calculation child
The variable focal length device according to claim 8 . 10. The shutter release section according to claim 10, wherein:
Based on the distance measurement result to the object in response to the operation of the material
And the amount by which the motor operates to change the focal length.
The focal length according to claim 8, wherein the calculation is performed.
Transformers . 11. A first straw for a shutter release member.
For focus adjustment and focal length change in response to
Calculate the amount of operation of the motor and the shutter release.
Calculation result in response to a second stroke operation of the closing member
Control means for operating the motor in accordance with
The focus according to any one of claims 1 to 6, wherein
Point distance variable device . 12. The motor is a stepping motor.
The method according to any one of claims 1 to 11, wherein
Variable focal length device . 13. The first lens unit is moved in a predetermined direction.
Having an elastic member for urging the member
13. The variable focal length device according to claim 1 . 14. The second lens unit is moved in a predetermined direction.
Having an elastic member for urging the member
A variable focal length device according to any one of claims 1 to 13 . 15. The first lens unit according to claim 15, wherein
The stop position of the knit with respect to the second lens unit is determined.
The method according to any one of claims 1 to 14, wherein
The variable focal length device as described in the above . 16. The camera according to claim 16, wherein the first lens unit is a shutter.
2. The electronic device according to claim 1, wherein
16. The variable focal length device according to any one of claims 15 to 15 . 17. The moving means, comprising: a focal length changing operation unit.
The operation starts in response to the operation of the material, and the focal length changing unit
After releasing the operation of the material, the first and second lens units
And that the motor has reached a predetermined position.
Stopping the operation in response to the request
17. The variable focal length device according to any one of 1 to 16 . 18. After photographing, the second lens unit is
Move to a predetermined position with respect to the first lens unit,
Starting means for operating the motor so that
The focus according to any one of claims 1 to 17, characterized in that:
Variable distance device . 19. The second position for movement to a storage position.
Connect the lens unit to the first lens unit
Characterized in that the motor is operated so as to be close to the motor
A variable focal length apparatus according to any one of claims 1 to 18.
Place . 20. The second lens unit, wherein:
It is movably held by one lens unit.
The focal length according to any one of claims 1 to 19,
Transformers . 21. The first lens unit, wherein the motor is
21. The device according to claim 20, wherein
Variable focal length device . 22. A first lens unit and a second lens unit.
Lens unit and the second lens unit to the first lens unit.
A motor that moves with respect to the lens unit;
1. Optical axis integrally including the second lens unit and the motor
Moving means for moving in the direction, and moving by the moving means.
The stop position of the first lens unit to be moved is determined.
Determining means for determining
The second lens moved by the motor
Moving position of the unit with respect to the first lens unit
And deciding means for deciding the turtle.
La . 23. A shutter release member comprising:
It is characterized by having control means to act in response to the operation
The camera according to claim 22, wherein: