JPH07140370A - Driving controller for zoom lens - Google Patents

Abstract

PURPOSE:To reduce the extended amount of a lens barrel, to shorten driving time, and to simplify an interlocking mechanism between a finder optical system and a flashing unit for illumination and a tele-macro photographing mechanism in a zoom lens for a camera motor-driven without using a cam barrel. CONSTITUTION:A front group lens 45 and a rear group lens 56 are integrally moved by a DC1, and only the rear group lens 56 is moved by a DC2, so that zooming is performed. The DC1 and the DC2 are driven and controlled according to a zooming position and encoder pulses detected by a 1st code substrate 59, a 1st code brush 60, a 2nd code substrate 62, and a 2nd code brush 61. Then, focusing is performed by the driving of the DC1 at a wide end and the driving of the DC2 at other zooming positions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens drive controller for a camera equipped with a finder optical system having a structure different from that of a taking lens.

[0002]

2. Description of the Related Art A zoom lens provided in a camera has a cam frame having a long and narrow cam hole along the periphery thereof, and a cam follower protruding into the cam hole fixedly attached to the zoom lens, and is mounted inside the cam frame to form a photographing lens. In many cases, a plurality of moving frames supported by the cam frame are rotationally driven to move the moving frames, and the photographing lens is displaced in the optical axis direction to change the magnification.

However, since such a zoom lens uses a cam frame which requires high accuracy in design and production, it becomes a high-cost product, and therefore a zoom lens which does not use any cam frame is used today. Murens is being developed.

FIG. 17A is a simplified diagram of a zoom lens configured to drive a motor without using a cam frame. As shown in the figure, a first moving frame 13 is provided in the fixed frame 11 so as to move along the optical axis 12.

A shutter mounting frame 14 is fixed to the first moving frame 13, and a front lens group 15 is mounted on the shutter mounting frame 14. It should be noted that shutter blades are provided on the back side of the shutter mounting frame 14.

The first moving frame 13 is connected to a drive ring 16 and is pushed out by the drive ring 16 and pulled back. That is, the male helicoid screw provided on the outer side of the drive ring 16 is screwed into the female helicoid screw on the inner surface of the fixed frame 11, and the drive ring 16 is
It is driven to rotate by the motor 17 and moves in the optical axis direction,
The first moving frame 13 is moved back and forth without rotating.

A rear lens group 18 is provided inside the first moving frame 13.
A second moving frame 19 to which is attached is provided. This second
A part of the moving frame 19 is screwed into a lead screw 20 pivotally supported by the first moving frame 13, and the lead screw 20 is rotationally driven by a second motor 21 arranged in the shutter mounting frame 14. As a result, the second moving frame 19 moves the optical axis 12
Move along.

FIG. 17A shows the zoom lens retracted into the camera. When the main switch is turned on in this collapsed state, first the first motor 17 is driven to rotate in one direction. The ring 16 is moved forward while rotating. Therefore, the first moving frame 13 is extended to the shooting position shown in FIG.

When the first moving frame 13 is moved to this photographing position, the detection signal causes the first motor 17 to stop and the second motor 21 to rotate. As a result, the second
The moving frame 19 moves backward as shown in FIG.
The shooting state of E is set.

When photographing in the WIDE state, the first motor 17 is driven to rotate again in accordance with the release and focusing is performed. In other words, the movement of the first moving frame 13 causes both the front lens group 15 and the rear lens group 18 to move, thereby performing focusing.

For zooming, the first motor 17 is rotationally driven, the first moving frame 13 and the second moving frame 19 are both fed out, and then the second motor 21 is rotationally driven to the second. Only the moving frame 19 is moved.

For example, at the WIDE end of FIG.
When the lens is moved, the front lens group 15 and the rear lens group 18 advance together, and the state at the TELE end becomes as shown in FIG. After that, the second motor 21 is rotationally driven, and as shown in FIG.
The rear lens group 18 moves forward as shown in FIG.
Will be in the shooting state.

After zooming in this way, the first mode is set.
Focusing is performed by rotating the motor 17 according to the release, but when distance measurement is performed at a distance closer than the closest distance, the second mode is activated in response to the release operation.
The lens 21 is driven to rotate, and the rear lens group 18 is displaced to a predetermined position for telemacro focusing.

The zoom lens described above has already been applied for a patent as Japanese Patent No. 358,015 of 1991.

[0015]

In the conventional zoom lens described above, after zooming, the first motor 17 is driven to rotate, and the lenses 15 in the front and rear groups at each zooming position.
Since the lens 18 is extended and focused, the lens driving amount becomes large and the lens driving time becomes long.

When the image magnification of the finder optical system is changed in conjunction with the zooming operation of the zoom lens or the irradiation angle of the illumination flash unit is changed, the image magnification or the irradiation angle is changed. In addition to the zooming operation, the focusing operation causes a change. Therefore, it is necessary to provide a special constituent means for keeping the image magnification or the irradiation angle unchanged depending on the focusing operation.

Furthermore, in the above zoom lens, the movement of the lens becomes complicated during macro photography. That is, when the distance measurement is performed at a distance closer than the closest distance, the second motor 21 is rotationally driven after the front lens group 15 is moved forward in response to the release operation, and the rear lens group is rotated. The lens 18 is displaced to a predetermined position to perform telemacro focusing.

In view of the above situation, the present invention has developed a zoom lens drive control device which solves the above-mentioned problems by electrical control means without changing the mechanical or optical configuration of the lens barrel. The purpose is to do.

[0019]

In order to achieve the above-mentioned object, in the present invention, at least two or more lens groups that move by zooming and the same number of lenses as the moving lens groups are used.
And a position detecting means which is provided for each lens group to detect the lens group position by code detection and counting of encoder pulses, and controls each motor according to the detection of this position detecting means. In a zoom lens configured to perform zooming and focusing, among zooming positions detected by the above position detecting means,
A motor for focusing by moving all the lens groups at the zooming position where the lens is least extended and by moving the other lens groups except the lens group closest to the subject at other zooming positions. A drive control device for a zoom lens, which is equipped with a control means, is proposed.

[0020]

The drive control apparatus of the present invention detects the code at the WIDE position in accordance with the preceding operation of the shutter button when shooting is performed at the zooming position where the lens is most extended, for example, the WIDE position. , Rotate the motor.

By this rotational driving of the motor, the entire lens group is moved toward the TELE side, and the pulses of the encoder interlocked with the motor are counted. When the count value of the encoder pulse has a predetermined relationship with the distance measurement value, the motor is stopped, and the lens position at that time is used for focus matching.

In the case of photographing at other zooming positions, the zooming position of the lens is detected according to the previous operation of the shutter button, and the motor is rotationally driven by this code detection. In this case, the lens groups other than the lens group closest to the subject are moved, and the encoder pulse is counted. Then, when the count value of the encoder pulse has a predetermined relationship with the distance measurement value, the motor is stopped and the lens position at that time is used for focus matching.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will now be described with reference to the drawings. FIG. 1 is a front view of a lens barrel of a zoom lens provided in a camera having a finder optical system different from the taking lens, FIG. 2 is a sectional view taken along the line AA in FIG. 1, and FIG. FIG. 4 is a sectional view taken along line BB in FIG. 1, FIG. 4 is a sectional view taken along line CC in FIG. 1, and FIG. 5 is an end view taken along line DD in FIG. The lens barrel can be housed in the camera body. In these drawings, 31 is a fixed frame, 32 is a first moving frame, 33 is a second moving frame, 34 is a first motor, and 35 is a second motor.

The fixed frame 31 is a cylindrical frame body, and a flange 31a provided at the rear end of the fixed frame 31 is attached and fixed to the camera body. As shown in FIGS. 1 and 2, a helicoid screw (female) 31b is provided on the inner surface of the fixed frame 31, and a drive ring 36 provided inside the fixed frame 31 is screwed to the helicoid screw 31b. is doing.

That is, the drive ring 36 is provided with a helicoid screw (male) 36a on its outer periphery, and this helicoid screw 36a is screwed into the helicoid screw 31b of the fixed frame 31. Further, the drive ring 36 has a gear 36b formed on the outer periphery on the front side (the outer periphery on the right end side in FIG. 2), and the gear 36b is driven by the output gear described later to rotate.

The drive ring 36 is connected to the first moving frame 32 by a friction spring 37. That is, the other end side bent portion of the friction spring 37 whose one end is fixed to the locking projection 32a of the first moving frame 32 is pressed against the rear surface of the drive ring 36. By this connection, the drive ring 36 that rotates in accordance with the helicoid screw advances and retracts the first moving frame 32 that moves without rotating. The friction springs 37 are provided at four positions above and below the drive ring 36 (FIG. 1). Further, the friction spring 37 has the first
Although it is configured separately from the moving frame 32, it can be configured integrally with the first moving frame 32.

On the other hand, on the inner surface of the above-mentioned fixed frame 31, key grooves 31c linearly provided in the front-rear direction are provided at three equal positions, and each is provided around the rear end of the first moving frame 32. Key
32b is projected into these key grooves 31c.

The first moving frame 32 is a circular frame having a diameter slightly smaller than that of the fixed frame 31 and is installed in the fixed frame 31.
b is guided by the key groove 31c and moves in the optical axis direction (horizontal direction in FIG. 2) without rotating. That is, the helicoid screws 31b and 36a are pushed by the drive ring 36 which is rotated and moved, and are pulled and moved in the optical axis direction while not being rotated.

The drive ring 36, as detailed in FIG.
It is rotationally driven by an interlocking mechanism including an output gear 38, a reduction gear 39, a long gear 40, and a moving gear 41 of the first motor 34. The first motor 34 is a DC motor, which is attached to a fixed plate 42 provided on the fixed frame 31 and is pulse-controlled by using a photo interrupter 43. Note that 43
a indicates an encoder.

A reduction gear 39 interlocked with the output gear 38 and an elongated gear 40 interlocked with the reduction gear 39 are pivotally supported by the fixed frame 31. Further, the moving gear 41 interlocked with the long gear 40 is pivotally supported by the bearing upright portion 32c provided on the first moving frame 32 so that the gear 41 meshes with the gear 36b of the drive ring 36. .

By this interlocking mechanism, the rotational driving force of the first motor 34 is transmitted to the moving gear 41, and the moving gear 41
Causes the drive ring 36 to rotate. Therefore, the drive ring 36 moves according to the helicoid screws 31b and 36a, and moves the first moving frame 32 in the optical axis direction. At this time, the moving gear 41 moves along the long gear 40.

A shutter mounting frame 44 is screwed to the above-mentioned first moving frame 32, and a front lens group 45 is supported on a cylindrical portion 44a of this shutter mounting frame 44. A shutter blade 46 is provided near the rear surface side together with a shutter blade retainer. The shutter blades 46 are mounted on the outer periphery of the cylindrical portion 44a.
Opening and closing operations are interlocked by the drive source 47.

Further, the cylindrical portion 44a of the shutter mounting frame 44
A second motor for moving the second moving frame 33 is provided around the outer periphery of the second moving frame 33.
A switch 35 and its interlocking mechanism are provided. This interlocking mechanism
As shown in FIGS. 1 and 4, the output gear 4 of the second motor 35
8, reduction gears 49 to 52, an interlocking gear 53 fixed to the lead screw 54, and a cylindrical screw (female) 55 fixed to the rising portion 33a of the second moving frame 33.

The second motor 35 is a DC motor, and the first motor
Similar to the motor 34, pulse control is performed using a photo interrupter and an encoder. The interlocking gear 53 is the reduction gear 5 at the end.
It rotates in conjunction with 2. And this interlocking gear 53
Is the upright portion 33 of the shutter mounting frame 44 and the second moving frame 33.
The lead that has been pierced through a and pulled back (to the left in Fig. 4).
It is fixed to one end of the screw 54.

The lead screw 54 is arranged so that the interlocking gear 53 is pressed against the shutter frame 44.
The interlocking gear 53 side is urged by the pressing plate 58. Also,
A tubular screw 55 is screwed into the lead screw 54, and the tubular screw 55 is screw-fed by the rotation of the lead screw 54 to move the second moving frame 33 in the optical axis direction (see FIG. 4). Left and right).

The second moving frame 33 is a cylindrical frame which can be moved within the first moving frame 32, and the rear group lens 56 is supported by this. Then, as shown in FIG. 5, the second moving frame 33 is configured to move in the optical axis direction while being unrotated while being guided by the guide shaft 57 provided on the first moving frame 32.

That is, the second moving frame 33 is provided with a projecting arm 33b projecting forward (to the right in FIG. 5) through the notch 44b of the shutter mounting frame 44.
The guide shaft 57 is slidably passed through a shaft hole formed in the upstanding piece portions 33c and 33d of b. The guide shaft 57
Is pivotally supported by shaft stoppers 32d and 32e that project from the front and rear ends of the first moving frame 32 toward the inside of the frame.

On the other hand, the fixed frame 31 and the first moving frame 32 are provided with the first code detecting means as shown in FIGS. In this first code detecting means, a first code board 59 is attached so as to close the through hole 31d provided on the side surface of the fixed frame 31, and the first moving frame 32 is provided with the above-mentioned first code. A first cord brush 60 adapted to slide on the wiring board 59 is attached. The first code detecting means reads the code and detects the relative position between the fixed frame 31 and the first moving frame 32.

FIG. 6 shows a first code substrate 59,
a, 59b, 59c, and 59d are the respective code substrates (59
a is ground), ZC1 to ZC7 are zoom codes, ZP
1 to ZP6 are zoom positions, HP1 to HP6 are zoom positions.
The respective home positions corresponding to the front lens group 45 (first moving frame) when zoomed are shown. In addition, HP
Reference numeral 0 denotes a home position position corresponding to the front lens group 45 when the first moving frame 32 is housed in the camera body. In this case, the zoom code is ZC0 and the zoom position is Z.
It is P0.

The first moving frame 32 and the second moving frame 33 are provided with second code detecting means as shown in FIGS. The second code detecting means is the second code brush 61 mounted on the projecting plate portion 44c of the shutter mounting frame 44.
Attached to the protruding arm 33b of the second moving frame 33,
The second code substrate 62 on which the brush 61 is slid
And the relative position of the first moving frame 32 and the second moving frame 33 is detected.

FIG. 7 shows the second code substrate 62, which is HP1.
HP6 is a home position corresponding to the rear lens group 56 (second moving frame 33) when zoomed, and HP0 is a rear lens group 56 when the lens barrel is housed in the camera.
Home position corresponding to, A to D are separated
Is shown. Further, FIG. 8 shows the second code substrate 62 similarly to FIG. 7, but this figure shows the moving direction of the rear group lens 56 by focusing.

FIG. 9 is a simplified block diagram showing the drive control circuit of the lens barrel described above. As shown in the figure, the controller 63 inputs the ON / OFF signals of the main switch 64, the WIDE switch 65, and the TELE switch 66, and the first motor 34 (hereinafter referred to as DC1) and the second motor 34.
The controller 35 (hereinafter, referred to as DC2) is drive-controlled. As a result, the front lens group 45 and the rear lens group 56 move to perform zooming.

When the shutter switch 67 is operated after the end of zooming, the controller 63 drives and controls DC1 or DC2 again to perform focusing. Further, the controller 63 operates the shutter sequence circuit 68 after the focusing is finished to operate the shutter.

Next, FIG. 1 showing the operation of the controller 63.
The operation of the lens barrel described above will be described in detail with reference to the flowcharts of FIGS. The lens barrel described above is housed in the camera when the main switch 64 is turned off. In this housed state, the first code brush 60 contacts the HP0 position of the first code substrate 59, and The code brush 61 is B of the second code substrate 62,
It is in contact with either C or D.

(1) Main switch ON With the lens barrel housed, main switch 64
When turned on, the ZCO signal is input from the first code detecting means (59, 60) to the controller 63 and operates like the flow chart shown in FIG. (See Figure 6)

That is, when the main switch 64 is turned on, the controller 63 responds to the ZC0 signal and drives and controls DC1 to the TELE side. (FIG. 10, Step ST1
00, ST101) Therefore, the drive ring 36 rotates and the first moving frame 32 is extended from the storage position (HP0).

As the first moving frame 32 advances to the TELE side, the first code detecting means (59, 60) is code ZC.
Switching from 0 to ZC1 and the controller 63 starts counting encoder pulses from the time of inputting this ZC1 signal. (FIG. 10, steps ST103 and ST104)
The encoder pulse is output by the photo interrupter 43 provided in DC1.

By counting the encoder pulses, it is determined whether or not this count has exceeded the preset number of pulses at the WIDE end, and when this number of pulses has elapsed, the controller 63 controls the DC1 to stop. (FIG. 10, steps ST104, ST105)

When the DC1 is stopped in this way, the first code brush 60 moves to the position HP of the first code substrate 59.
Contact the position 1 and the front lens group 45 is WID at this position.
It means that it was extended to the E end.

The controller 63 drives and controls DC2 immediately after stopping DC1. (FIG. 10, Step S
T106) In this case, DC2 is driven to the WIDE side,
The rotation of the lead screw 54 causes the second moving frame 33 to move to W
Move toward the IDE side. As a result, the second code brush 61 advances toward the code A from any one of the codes B, C and D of the second code substrate 62.

By this operation, the second code detecting means (6
1, 62) is switched from the code B to the code A, the controller 63 recognizes the input of the code A signal, and the encoder pulse is counted from this point. (FIG. 10, Steps ST107, ST108) The encoder pulse is output from the photointerrupter interlocked with DC2.

When the pulse count has passed the preset number of pulses at the WIDE end, the controller 6
The DC 2 is stopped and controlled by 3. (FIG. 10, Step ST109, ST110) When the DC2 is stopped in this way, the second code brush 61 is moved to the second code substrate 62.
That is, the rear lens group 56 has moved to the WIDE end.

In this way, the main switch 64 is turned on.
Then, the lens barrel is extended from the storage position to the WIDE end and the photographing is possible.

Next, the zooming operation will be described.
Zooming is performed by operating the WIDE switch 65 and the TELE switch 66. By operating these switches 65 and 66, the DC1 is first driven and controlled.
The zooming operation is performed according to the flowchart shown in FIG.

(2) Zooming by DC1 When the TELE switch 66 is turned on in the state where the lens barrel is extended to the WIDE end as described above, the controller 63 which inputs the ON signal brings DC1 to the TELE side. Drive control. (FIG. 11, steps ST200 to ST20
3) Therefore, the first moving frame 32 advances and the front group lens 4
5 moves to the TELE side. Further, in this case, since the second moving frame 33 advances together with the first moving frame 32, both the front lens group 45 and the rear lens group 56 move toward the TELE side.

When the TELE switch 66 is continuously operated until reaching the TELE end, the first code detecting means (5
It is judged by the controller 63 whether or not (9, 60) has detected the code ZC6 immediately before the TELE end code ZC7. (FIG. 11, steps ST204, ST20
5) That is, the first code brush 60 is the first code substrate 5
The controller 63 recognizes this code ZC6 (current code Z) when the code ZC6 of 9 is contacted, and subsequently,
Encoder pulses are counted from the time when the first code brush 60 is switched from the code ZC6 to ZC7. (Fig. 1
1, steps ST206 to ST208)

When the count of the encoder pulse has passed the designated number of pulses, DC1 is stopped and controlled. At this time, the first moving frame 32 advances so that the first code brush 60 comes into contact with the position HP6 of the first code substrate 59, and the front lens group 45 moves to the TELE end. The controller 63 immediately shifts to drive control of DC2 after stopping DC1. (FIG. 11, step ST211) Driving of DC2 will be described later.

When the operation of the TELE switch 66 is released before reaching the TELE end, this switch 66 is turned off.
The zoom code (current code Z) at the time of FF is recognized by the controller 63. (FIG. 11, Step S
(T204, ST206) and thereafter, the operations of steps ST207 to ST211 are performed in the same manner as above.

For example, in the zoom position ZP3, TEL
Assuming that the operation of the E switch 66 has been released, the controller 63 recognizes the code ZC4 as the current code Z, and subsequently, the code which is one TELE side from this code ZC4. The encoder pulse counting is started from the time when the ZC5 is recognized. (FIG. 11, step ST20
4, ST206 to ST208)

Then, when the count of the encoder pulse has passed the designated number of pulses, the DC1 is stopped and the drive control of the DC2 is started. At this time, the first code brush 60 comes into contact with the position HP4 of the first code substrate 59,
The front lens group 45 is extended to the zoom position ZP4.

On the other hand, when the WIDE switch 65 is operated, the controller 63 drives and controls the DC1 to the WIDE side unless the lens barrel is at the WIDE end. (Fig. 1
1, step ST212, ST213) and WID
When the E switch 65 is continuously operated to zoom to the WIDE end, the controller 63 sets the WIDE end code Z.
Encoder pulses are counted from the time when C1 is recognized, DC1 is stopped when this pulse count has passed a specified number of pulses, and then drive control of DC2 is started.
(FIG. 11, steps ST214 to ST219) In this case, the first code brush 60 comes into contact with the position HP1 of the first code substrate 59, and the front lens group 45 is pulled back to the WIDE end.

When the operation of the WIDE switch 65 is released before the lens barrel reaches the WIDE end, the controller 63 recognizes the current code Y when the operation is released, and subsequently, It is determined when the current code Y is advanced to the WIDE side code, and the encoder pulse is counted from this point. (FIG. 11, step ST21
4, ST220 to ST222)

Then, when the pulse count reaches the preset number of bias pulses, the DC1 is stopped and the steps ST204, ST205 to ST21 already described.
Move to operation 1. That is, when the number of biased pulses has passed, DC1 is temporarily stopped and this DC1 is drive-controlled to TELE side. Then, the current code Z when the DC1 starts driving is recognized, and the encoder pulse is counted from the time when the code Z moves to the code on the TELE side,
When this pulse count exceeds the specified number of pulses, D
C1 is stopped, and then the drive control of DC2 is started.

The above zooming operation will be specifically described with reference to FIG. For example, when the operation of the WIDE switch 65 is released, the first code brush 60 is switched to the code ZC.
If it is the position a of 4, the controller 63 is connected.
The encoder ZC4 is recognized, and the encoder pulse is counted from the time when the brush 60 slides to the WIDE side and moves to the code ZC3. Then, at the position b of the code ZC3 where the pulse count has passed the number of biased pulses, DC
Stop 1 once.

Subsequently, the DC1 is driven and controlled to the TELE side, the controller 63 recognizes the code ZC3, and the encoder pulse starts when the first code brush 60 enters the code ZC4. To count. Then, the DC1 is stopped when the pulse count exceeds the designated pulse number. At this time, the first code brush 60 comes into contact with the position HP3 and the front lens group 45 is pulled back to the zoom position ZP3.

When the lens barrel is at the TELE end, TE
When the LE switch 66 is operated and the WIDE switch 65 is operated at the WIDE end, the controller 63 immediately recognizes the TELE end code ZC7 or the WIDE end code ZC1. -No ming operation is performed. (FIG. 11, Steps ST202, ST2
12)

As described above, after the front lens group 45 is moved to each zooming position by driving DC1, D
C2 is drive-controlled, and the rear lens group 56 moves to each zooming position according to the flowchart shown in FIG.

(3) Zooming by DC2 In this operation, the controller 63 sets the front lens group 45 to W.
It is determined whether it is at the IDE end. (FIG. 12, step ST300) If it is at the WIDE end, it is determined whether or not the current code is A (FIG. 7). (FIG. 12, Step S
(T308) At this time, the second cord brush 61 moves to the second cord.
If the code A is in contact with the code A of the board 62 and the code is currently A, the DC2 is rotationally driven to the TELE side, and when the code B is switched, the encoder pulse is counted. (FIG. 12, steps ST308 to ST311)

Then, when the pulse count reaches the number of biased pulses, DC2 is temporarily stopped, and then DC2 is rotationally driven to the WIDE side to reach the target code (code A in this case). When the encoder pulse is counted,
The DC2 is stopped when this count exceeds the specified number of pulses. (FIG. 12, Steps ST312, ST31
3, ST302 to ST305) Note that this operation is shown in FIG.
This is the same as the one-sided pulse control shown in. By this operation, the second code brush 61 comes into contact with the position HP1 of the second code substrate 62, and the rear lens group 56 becomes WI.
Move to the zooming position at the DE end.

When the front lens group 45 is at the WIDE end,
When the code brush 61 is not on the code A of the second code substrate 62, that is, when it is in contact with any one of the codes B, C and D, the DC2 is driven and controlled to the WIDE side. , The encoder pulses are counted from the time of switching to the target code A, the second code brush 61 comes into contact with the position HP1 and the rear lens group 56 receives the WID.
Move to the E end. (FIG. 12, Steps ST308, ST
302-ST305)

When the DC1 is stopped and the front lens group 45 is not at the WIDE end, the current code and the target code are compared. (FIG. 12, Steps ST300, ST30
1) The codes A, B, C and D are weighted and D
>C>B> A.

That is, when the target code for moving the rear lens group 56 is smaller than the current code (FIG. 7) at the time of shifting to the drive control of DC2, DC2 is drive-controlled to the WIDE side and the target code is moved. -The encoder pulse is counted at the time when the mode is advanced. Then, the DC 2 is stopped when the pulse count exceeds the designated number of pulses. (FIG. 12, steps ST301 to ST305)

For example, the current code is B, and the target code is
If the code is A, the DC2 is stopped when the encoder pulses counted from the switching points of the codes A and B have passed the designated number of pulses. Therefore, the second code brush 61
When the position reaches the position of HP1 or HP4, DC2 is stopped and the rear lens group 56 moves to the zoom position of the zoom position ZP1 or ZP4.

If the target code is larger than the current code, DC2 is driven and controlled to the TELE side, and when the target code is reached, the encoder pulse is counted, and the rear lens group 56 is operated in the same manner as above. To move. (FIG. 12, Step S
(T306, ST307, ST303 to ST305) This operation is a case where the target code required for zooming is B, C, D, assuming that the current code is A.

When the current code and the target code are the same when moving to the drive of DC2, DC2 is kept stopped. (FIG. 12, Steps ST301, ST30
6) For example, the front lens group 45 is set to the zoom position ZP4.
If the current code is A when moving to, the DC2 is not driven because the current code and the target code are both A.

At this time, the focusing operation (DC
2) to move the rear lens group 56 to a position corresponding to the position HP4. Positions HP2 and HP5
When and become the current code and the target code, position H
Similarly, when P3 and HP6 are the current code and the target code, the rear lens group 56 is moved by the focusing operation.

(4) Focusing After zooming as described above, the shutter switch 6
By operating 7, focusing is performed according to the flowcharts of FIGS. The small circles 69a and 69b in FIGS. 13 and 14 represent connectors.

Focusing is DC1 drive control when the lens barrel is at the WIDE end, and DC2 drive control when the lens barrel is at a position zoomed from the WIDE end. DC1 when the lens barrel is at the WIDE end
Is turned on to the TELE side, one code on the TELE side, that is, the code ZC2 is recognized, and the encoder pulse is counted from this point. (FIG. 13, FIG. 14, Step S
(T400, ST416 to ST418)

Then, when the pulse count exceeds the number of automatic distance measurement signal pulses (AF pulses), DC1 is stopped. (FIG. 14, Steps ST419 and ST420) In this focusing operation, the front lens group 45 and the rear lens group 5 are
6 is integrally fed out to control focusing. Then, the shutter sequence circuit 68 opens and closes the shutter. (FIG. 14, step ST421)

After the shutter operation, the DC1 is driven and controlled on the WIDE side, the encoder pulse is counted from the time when the WIDE end code ZD1 is recognized, and the DC1 is stopped when the pulse count reaches the designated pulse number. (Fig. 1
4, Steps ST422 to ST426) At this time, the first
The code brush 60 is at the position H of the first code substrate 59.
The lens barrel returns to the zoom position ZP1 at the WIDE end by contacting the position P1.

When the lens barrel is zoomed to a position other than the WIDE end, the zoom position ZP2 or ZP3 is set.
Or other zoom positions ZP4, Z
DC2 is drive-controlled by judging whether it is P5 or ZP6. (FIG. 13, steps ST400, ST40
1)

When the zoom position is ZP2 or ZP3, DC2 is driven and controlled to the WIDE side, the encoder pulse is counted from the time when the target code is reached, and when the pulse count exceeds the AF pulse number, DC2 To stop. (FIG. 13, steps ST402 to ST407)

For example, the lens barrel is at the zoom position Z.
If it is in P2, as shown in FIG.
By controlling the drive to the E side, the second cord brush 61
Encoder pulses are counted from the time when the code has reached the switching point between the code A and the code B, and when the pulse count exceeds the number of AF pulses, the DC2 is stopped and focus control is performed.
When the lens barrel is in the zoom position ZP3, the encoder pulses are counted from the time of the switching points of the codes B and C, and the same focusing control is performed.

The lens barrel has a zoom position ZP4 to ZP.
If either of P6 is set, DC2 is TELE
When the target code is reached, the encoder pulses are counted. And the pulse count is A
When the number of F pulses has elapsed, DC2 is stopped and focus control is performed. (FIG. 13, steps ST403 to ST407)

For example, if the lens barrel is at the zoom position Z
If it is in P4, the encoder pulses are counted from the switching points of the codes A and B as shown in FIG.
Is stopped and the focus is controlled. When the lens barrel is in zoom position ZP5 or ZP6, code B, C
Alternatively, encoder pulses are counted from the switching points C and D, and focusing control is performed in the same manner as above.

After the focusing described above, the shutter release is performed.
The shutter is opened and closed by the operation of the can circuit 68, and then the rear lens group 56 is returned to the original zoom position. (FIG. 13, step ST408)

This return control is divided into the zoom position ZP2 or ZP3 and other zoom positions in the same manner as described above. DC2 is set to the TELE side during focusing at the zoom position ZP2 or ZP3. At the time of focusing at other zoom positions, DC2 is driven and controlled to the WIDE side. (FIG. 13, step ST409,
ST411) Then, when each target code is reached, encoder pulses are counted, and when the pulse count reaches the designated number of pulses, DC2 is stopped. (Fig. 13,
(Steps ST412 to ST415)

(5) Main switch OFF When the main switch 64 is turned OFF, the flow shown in FIG.
The lens barrel is housed in the camera body according to the chart. In this storing operation, the code of the second code board 62 is
If the rear lens group 56 is located at a position corresponding to any one of the codes B, C and D, DC1 is set to WIDE
Drive control to the side. (FIG. 15, Step ST500, S
T506)

The second code brush 61 is OFF code, that is, the position ZP0 of the first code substrate 59.
When the encoder pulse is counted from the point of contact with the
Stop C1. In this case, the first code brush 60 contacts the position HP0 of the first code substrate 59, and the lens barrel moves to the storage position.

When the rear lens group 56 is in the position corresponding to the code A of the second code board 62 when the main switch 64 is turned off, the DC2 is driven and controlled to the TELE side, and the code is The encoder pulse is counted from the time when the de B is recognized. (FIG. 15, steps ST500 to ST
503)

Then, when the pulse count exceeds the designated number of pulses, DC2 is stopped. (FIG. 15, Steps ST504 and ST505) By this operation, the rear lens group 56 approaches the front lens group 45, and then DC1 is drive-controlled, and the process proceeds to the above-mentioned steps ST506 to ST510, and the lens barrel moves to the storage position. .

[0092]

As described above, according to the drive control device of the present invention, the entire lens group is moved at the zooming position where the lens is least extended, and the objective lens is used at the other zooming positions. Since focusing is performed by moving the other lens groups except the lens group, the lens driving amount is reduced and the lens driving time is also shortened.

Further, since the finder optical system and the flash device for illumination need only be interlocked with the moving frame supporting the objective lens, the interlocking mechanism is not related to focusing,
The structure of the interlocking mechanism becomes simple. Further, since the macro photographing mechanism can be configured to move the lens group other than the objective lens, the structure therefor becomes simple.

[Brief description of drawings]

FIG. 1 is a front view showing a lens barrel of a zoom lens embodying the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a sectional view taken along line BB in FIG.

FIG. 4 is a cross-sectional view taken along the line CC of FIG.

5 is an end view taken along line D-D in FIG. 1. FIG.

FIG. 6 is a first graph showing a zooming operation of the front lens group.
FIG.

FIG. 7 is a second lens diagram showing the zooming operation of the rear lens group.
FIG.

FIG. 8 is a simplified diagram of a second code substrate showing a focusing operation.

FIG. 9 is an electrical block diagram showing an embodiment of the drive control device of the present invention.

FIG. 10 is a flowchart showing an operation of turning on a main switch.

FIG. 11 is a flowchart showing a zooming operation by DC1.

FIG. 12 is a flowchart showing a zooming operation by DC2.

FIG. 13 is a flowchart showing a focusing operation.

FIG. 14 is a flowchart showing a focusing operation.

FIG. 15 is a flowchart showing an operation of turning off the main switch.

FIG. 16 is a partial schematic view of a first code substrate for explaining a zooming operation.

FIG. 17 shows a conventional zoom lens, as shown in FIG.
(B) and (C) are simplified diagrams showing an operation process of extending the zoom lens to a photographing position.

FIG. 18 shows a zooming operation process of the conventional zoom lens, FIG. 18 (A) shows a state in which a front lens group and a rear lens group are integrally advanced, and FIG. It is a simplified diagram which shows the state which advanced the lens, respectively.

[Explanation of symbols]

 31 Fixed Frame 32 First Moving Frame 33 Second Moving Frame 34 First Motor (DC1) 35 Second Motor (DC2) 36 Drive Ring 37 Friction Spring 43 Photointerrupter 44 Shutter Frame 45 Front Group Lens 54 Re- Screws 56 Rear lens group 59 First code substrate 60 First code brush 61 Second code brush 62 Second code substrate 63 Controller 64 Main switch 65 WIDE switch 66 TELE switch 67 Shutter switch

Claims (1)

[Claims] 1. At least two or more lens groups that move by zooming and as many motors as there are moving lens groups are provided, and a code is provided for each lens group to detect the lens group position. And a position detecting means for detecting by counting the encoder pulse, the zoom lens having a structure for controlling zooming and focusing by controlling each motor according to the detection of the position detecting means. Of the zooming positions detected by the detecting means, at the zooming position where the lens is least extended, all the lens groups are moved, and at the other zooming positions, the lens group closest to the subject is excluded. A drive control device for a zoom lens, comprising a motor control means for moving a lens group for focusing.