JPH045607A - Lens driver - Google Patents

Abstract

PURPOSE:To reduce the load on a power source and to eliminate the dynamical mutual interference of a lens group by outputting the position where the lens group ought to be positioned, driving and controlling each lens group while detecting the position of the lens group. CONSTITUTION:A power focusing mode is entered with the button of a focusing operation input part 601 pressed. The initial position of a 2nd group lens 72 is read in. The direction and distance of movement of the lens 72 are outputted. The movement distance is a prescribed quantity delta in slow-speed mode to make image variation due to lens group movement small by single-time driving and 3delta in high-speed mode. This value is added to the read position of the lens 72 to output the target position. The position of a 3rd group lens 73 corresponding to the target position of the lens 72 is calculated. A photo-MOS relay is turned on to output a driving signal by a driving circuit 54 under the control of a control part 57, and the lens 72 is driven; and its position is read out and when the lens 72 reaches the target position, the driving signal is ceased. A 3rd lens group 73 is also driven similarly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lens driving device for driving a lens in a camera equipped with a photographing lens that can move the lens in the optical axis direction for the purpose of zooming or focusing.

[Prior Art] Conventionally, zooming and focusing systems have been configured such that a cam barrel provided with a cam groove guides a pin provided in a lens frame, and the positional relationship of the lenses is set in a predetermined state. Photographic lenses with these functions have been widely used in cameras.

In order to perform zooming and focusing functions and obtain a high-quality image, such photographic lenses use the cam grooves to ensure a pre-designed positional relationship between the lenses. The respective functions are achieved by manually driving the cylinder with a mechanically interlocked operating ring or rotating it with a mechanically interlocked motor.

On the other hand, a method has also been proposed in which each lens group is provided with its own actuator and each lens group is driven independently, as shown in, for example, Japanese Unexamined Patent Publication No. 52-114321.

[Problem to be solved by the invention] In recent years, with the remarkable progress in electronic technology, zooming and focusing of the lens can be performed by various actuators, and the amount of drive can also be determined from the output of an autofocus sensor or an electronic dial for manual operation. It is calculated and set automatically. These technologies have shortened the time required to drive the vehicle and made it easier to operate.

On the other hand, there is a tendency for the burden on the DC power supplies built into cameras and photographic lenses to increase. Among these, the power consumption for driving the actuator has a large influence. Furthermore, since the cam barrel had to be rotated to drive the lens and the lens to be moved had to be driven between multiple groups, a large amount of current was required to drive the lens, leading to faster consumption of the power source. Furthermore, if the actuator is driven at a low speed to prevent this, there is a drawback that the above-mentioned high speed is lost.

In addition, as a way to solve the above problem, it is possible to provide a high-speed actuator that drives each lens group independently and to improve the drive timing, but the position range of the lens groups that are driven and moved overlaps. If there is a risk of mechanical mutual interference, and in the case of a TTL camera, the amount of movement is large, the lens position relationship that was assumed at the time of design may deviate significantly, resulting in unexpected deterioration of the image. There have been problems such as the possibility of causing discomfort to the photographer looking through the viewfinder and making it difficult to operate the camera while looking through the viewfinder.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a lens driving device that reduces the burden on the power supply, eliminates the fear of mechanical mutual interference between lens groups, and allows lens operation while looking through the finder of a TTL camera. do.

[Means for Solving the Problems] A lens driving device of the present invention includes a plurality of lens groups movable in the optical axis direction, a plurality of driving means for respectively driving the plurality of lens groups, and a plurality of driving means for driving the driving means. a drive control means for generating a drive signal for the purpose of driving; a switching means for switching and transmitting the drive signal generated from the drive control means to one of the plurality of drive means; and a drive target for each of the plurality of lens groups. drive target position output means for outputting a position; first control means for outputting a control signal for controlling the switching operation of the switching means in order to sequentially drive each of the plurality of lens groups by a minute amount; and a second control means for repeating driving and outputting the control signal repeatedly until each of the plurality of lens groups reaches the drive target position.

[Function] In the lens driving device of the present invention, the positional relationship of the lens groups is not guaranteed by conventional means such as a cam cylinder, but the target position of the lens groups is outputted. The system attempts to ensure the positional relationship of the lens groups by outputting an output from the cam tube and controlling the drive of each lens group independently while detecting the position of the lens group based on the output. By eliminating friction and staggering the drive timings of each lens group so that they do not overlap, the current required at negative times is reduced and the burden on the power source is reduced. Moreover, since the amount of movement per time is small and the drive is performed along a predetermined positional relationship, there is no fear of mutual mechanical interference, and lens operation can be performed while looking through the finder of a TTL camera.

[Examples] Examples of the present invention will be described below with reference to the drawings.

First, as a first embodiment, a camera equipped with a single focus lens that has a four-group lens configuration and performs focusing using two groups will be described below.

FIG. 2 shows the lens configuration and frame configuration.

That is, the first group lens 71 and the fourth group lens 74 are fixed to a fixed frame 75, and during focusing, the second group lens 72 and the third group lens 73 are extended from infinity to close range by the amount shown in FIG. . Second group lens 72
and two front frames 76 and 3 that hold the third group lens 73.
The front frame 77 is guided by bearings 78 and 79 disposed on the inner circumference of the fixed frame 75 so that it can move inside the fixed frame 75 only in the optical axis direction, and is It is pressed in the direction of the bearing 78.79 by a vibrating body 80.81 disposed on the fixed frame 75 at a position approximately symmetrical with respect to the axis. Therefore, the second front frame 76 and the third front frame 77 each include each bearing 78.79 and each vibrating body 80.81.
As a result, there is no deviation in the position in the optical axis direction or the center of the optical axis with respect to the fixed frame 75, and the lens is also positioned without any wobbling.

Next, the details of the installation of the vibrator and the operation of the linear ultrasonic motor will be described. Although two linear type ultrasonic motors are used in this embodiment, since the installation and operation are the same, the linear type ultrasonic motors used for the two front frames 76 will be described as a representative.

FIGS. 4 and 5 are diagrams showing details of the linear ultrasonic motor. That is, inside the fixed frame 1 (75), which is a fixed member made of a hollow cylindrical body, the front frame 2 (76), which is a movable member also made of a hollow cylindrical body, is located at the center with a certain gap. It is arranged so that it can move in the zero axis direction. A slide plate 3 extending in the direction of the central axis O of the second front frame 2 is fixed to a part of the upper part of the gap between the fixed frame 1 and the second front frame 2 (in FIG. 4). and
In the middle part of the fixed frame 1 facing the slide plate 3, there is a rectangular notch hole 1 which is long in the front and back direction of the central axis O direction.
d (see Figure 5) is drilled. This notch hole 1d is a hole for arranging a vibrating body 12 (80), which will be described later.

On the other hand, a support guide mechanism for the two front frames 2 is provided in the gap opposite to the gap in which the slide plate 3 is provided. In this embodiment, this support and guide mechanism is composed of three guide grooves and a support body made up of a plurality of bearing balls disposed in each of the grooves. That is, at opposing positions across the central axis O of the slide plate 3, a straight groove 2b consisting of a partially arcuate recess is bored in the outer peripheral surface of the second front frame 2 in the direction of the central axis O of the second front frame 2, Straight groove 2 on the inner peripheral surface of fixed frame 1
In the middle of the position facing b, a linear groove 1b consisting of four partially arcuate parts is provided in the direction of the central axis O of the fixed frame 1. At positions equidistant from each other, there are straight grooves 1a and 2a, which are also made of partially arcuate recesses.

lc and 2c are bored in the outer circumferential surface of the fixed frame 1 and the inner circumferential surface of the front frame 2, respectively, toward the central axis O direction. In the straight grooves 1a, 2a, lb, 2b and lc, 2c, a support body 13a consisting of a plurality of bearing balls,
13b and 13c are provided, respectively.

In this support guide mechanism, the support body 13b of the front frame 2 is
When a vibrating body 12 (described later) disposed in a position facing
A centripetal action is exerted by ~13c, and the front frame 2 is connected to the fixed frame 1.
It is placed accurately and precisely so that the central axis coincides with the

Moreover, since the supports 13a to 13C have a plurality of bearing balls arranged in the direction of the central axis O of the fixed frame 1,
2. The front frame 2 is supported without any deviation of the central axis. moreover,
Since the support of the 2-front frame 2 is performed only by the supports 138 to 13C, only the straight grooves 1a to 1c and 2a to 2C of the 2-front frame 2 and the fixed frame 1 should be machined with high precision. For example, the second front frame 2 can be accurately positioned with respect to the fixed frame 1.

As shown in FIG. 4, the notch hole 1d is fixed P? ! It is bored in the middle of the upper part of the slide plate 1 so as to face the slide plate 3. That is, a flat part is formed by cutting the middle of the upper peripheral surface of the fixed frame 1 in a direction perpendicular to the central axis O, and a notch hole 1d consisting of an axially long rectangular through hole is formed in the center of the flat part.
It is perforated.

Therefore, on both sides of the notch hole 1d in the axial direction, there are flat portions 1d.
o is formed, and this plane portion 1do serves as a mounting portion for the holder 8 that supports the vibrating body 12.

The vibrating body 12 is composed of a bending vibrator 11 and a vertical vibrator 4. The bending vibrator 11 includes a relatively thick rectangular elastic body 5 that is arranged within the notch hole 1d with a margin, and a rectangular piezoelectric body 6 that is shorter in length and thinner than the elastic body 5. The piezoelectric body 6 is fixed to the upper surface of the elastic body 5 using an epoxy adhesive. and,
A driving high-frequency voltage is applied to the piezoelectric body 5 of the bending vibrator 11 in the thickness direction thereof, and in the case of this embodiment, a first-order bending resonance is generated. ing. At the two nodes of this bending vibration, a vertical vibrator 4 that vibrates longitudinally in the thickness direction of a laminated plate formed in a rectangular column shape of a laminated piezoelectric body is bent on the lower surface of the elastic body 5 to which the piezoelectric body 6 is not fixed. It is fixed so as to vibrate longitudinally in the thickness direction of the vibrator 11.

Further, the bending vibrator 11 has four cylindrical support pins 7 fixed to the elastic body 5 that extend outward in the board width direction of the bending vibrator 11 at the node positions thereof. A holder attachment groove 7a is provided in the middle of the pin 7 in the circumferential direction.

The vibrating body 12 configured in this way has a channel-shaped cross section and is housed and held from below in a holder 8 formed in a shape to cover the vibrating body 12 from above. That is,
The holder 8 is formed by bending an elastic thin plate, and has an oval hole-shaped receiving portion 8a with an open bottom at a position corresponding to the support pin 7 on the hanging wall of the holder 8. The lower open portion 8a is formed with a notch having a width slightly smaller in diameter than the diameter of the holder attachment groove 7a. Further, in the middle of the rain hanging wall of this holder 8, mounting fixing parts 8b are provided which are bent outward and extend horizontally, and the mounting fixing parts 8b are provided with fixing screws]0. Opening holes 8C are formed through which the holes 8C pass through, respectively.

The vibrating body 12 is housed in the holder 8 so as to be able to vibrate freely by loosely fitting the holder mounting groove 7a of the support pin 7 into the receiving part 8a, and then opening the holder 8. The vibrating body 12 is attached to the fixed frame 1 by passing the fixing screw 10 through the plate spring 9 and screwing the fixing screw 10 into the screw hole 1e screwed into the flat part 1do of the fixed frame 1. It is arranged in the notch hole 1d of. In this arranged vibrating body 12, the lower end surface of the vertical vibrator 4 is pressed against the upper plane of the slide plate 3 fixed to the two-way frame 2.

The operating principle of the ultrasonic motor configured as described above is the same as that of Japanese Patent Application No. 1-195767, which was previously proposed by the applicant. An elliptical vibration that moves the two-solution frame 2 back and forth in the direction of its central axis O is generated on the end face of the longitudinal vibrator 4. The two longitudinal oscillators 4 are configured to vibrate with a phase difference of 180'', so that only one direction movement of the pendulum vibration around the nodes due to bending vibration can be detected by the sliding plate 3 of the two solution frames 2.
to act on. Therefore, this causes the two-solution frame 2 to move forward and backward in the direction of the central axis O.

Next, the configuration of the electric circuit of the first embodiment will be explained with reference to FIG. In the figure, 52° and 523 are the second
Linear ultrasonic motors 512 and 513 corresponding to the vibrating bodies 80 and 81 in the figure are encoders that are driven by the ultrasonic motors 52□ and 523 and detect the movement of the frame. Encoder 51□.

513 consists of a scale with graduations written in two rows at equal intervals and shifted in phase, and a reading section.On the scale, another row of graduations indicating the end position serving as a reference value is also written. There is. In this case, the scale is arranged in the fixed frame 1, and the reading section is arranged in the 2-solution frame 76 and the 3-solution frame 77, respectively.

When the reading section moves relative to the scale, a pulse is generated and output at the position where the scale passes.

532 and 533 are direction detection circuits, and the encoder 51
The direction of movement is detected from the phase inversion of two series of pulses with different phases generated by No. 2,513.

552 and 553 are up/down counters that count encoder pulses from the end position, and 54 is an arithmetic control unit 5.
A drive circuit 59 drives the ultrasonic motors 522 and 523 made up of vibrating bodies 80 and 81 based on the drive control signal from 7, and 59 drives the pulses generated by the drive circuit 54 to either one of the ultrasonic motors 522 and 523. This is a switching circuit.

The drive circuit 54 and switching circuit 59 are shown in FIG. Note that the drive circuit 54 is the same as, for example, the third embodiment of Japanese Patent Application No. 1337024, so the details will be omitted. The switching circuit 59 also includes, for example, a photo MOS relay PM12, PM13, etc. as shown in FIG. PM22. PM23, which is opened and closed by a control signal from the calculation control section 57.

56 is a ROM that supplies programs and various memory data necessary for arithmetic control, which will be described later; 581; AF (autofocus) module using the ItTTL phase difference detection method; 601 is a focusing operation input unit for manual focusing; 60□ is an AF/AF switch that switches between AF (autofocus) and PF (power focus).
This is a PF switching section. 57 is an arithmetic control unit, which includes the outputs of up/down counters 55□ and 553, and the AF module 58.
output, output of focusing operation input section 601, AF
/PF switching unit 602 as appropriate and outputs a drive control signal for driving the ultrasonic motors 522 and 523 to the drive circuit 54.

FIG. 3 is an overview diagram of the zoom lens and camera in the first embodiment. That is, the camera body 91 has
A release button 92 that can output signals for first release (first release when pressed halfway) and second release when pressed fully, a finder 93 that uses a pentaprism to determine the angle of view, a quick-return main mirror 94 that guides the optical path to the finder 93, a sub-mirror 95 attached to the main mirror 94 and guiding light from the center to the AF module 58 at the bottom of the body;
and an AF module 58 are provided. Also, on the lens 96 side, there is a focusing operation input section 601 that can output half-press and full-press signals used during manual focusing (power focusing), and an AF
/PF switching section 602 is provided.

Next, based on the flowchart shown in FIG.
Power focusing of a camera according to an embodiment will be explained. First, when a button on the focusing operation manual unit 60 is pressed, a power focusing mode is entered. Next, the initial position of the second group lens 72 is read (Fl). Then, it determines whether the operated button is a retract button or an extend button, and whether it is pressed halfway or fully corresponding to low-speed operation, and outputs the direction and the distance traveled by the second group lens 72. (F2-F8). The moving distance is set so that there is less image change due to lens group movement in one drive at low speeds.
A predetermined constant amount δ is set, and when the speed is high, it is set to 3·δ. The second group lens 72 read out this value in step F1.
In addition to the position, output the target position (F9) Third group lens 73 corresponding to the target position of this second group lens 72
The position of is calculated using the formula described below (F10). With the above, the second lens group 72 and the third lens group for this operation are explained.
This means that the position of the group lens 73 is output.

Next, Photomos relay PM12. Turn on the PM 22 (Fll), and the drive circuit 54
starts driving the second group lens 72 by outputting a drive signal (F12).

The arithmetic control unit 57 repeatedly reads out the position of the second lens group 72 to determine whether the second lens group 72 has been driven to the target position (F13), and stops the drive signal when the target position is reached. The driving of the second group lens 72 stops (
Fl4). After the driving of the second group lens 72 is stopped, the photo MOS relay PM12 and PM22 are turned off, and the second group lens 72 is turned off.
One drive of is completed (F15).

The third lens group 73 is also driven in exactly the same way as the second lens group 72 (F16 to F20). Thereafter, it is determined whether the focusing operation has been completed (F21), and if it has not been completed, the process returns to step F2, and if it has been completed, the power focusing mode is ended.

Here, a method for outputting the target position of the third group lens 73 corresponding to the calculated target position of the second group lens 72 will be explained. In this embodiment, the target position of the third group lens 73 is approximately determined using a mathematical formula. The curve showing the relationship between the amount of movement of the second lens group 72 and the third lens group 73 as shown in FIG. 9 can also be approximately regarded as a combination of several line segments. Therefore, a plurality of coefficients a and b are stored depending on the position of the second group lens 72, and the target position X31 of the third group lens 73 is calculated by X31-aX21+b.

With this method, the target position of the third group lens 73 can be easily calculated with sufficient accuracy for practical use. Here, X21 is the target position of the second group lens 72.

If you drive according to the procedure described above, in the case of low speed drive, the 6th
On the graph in the figure, first, the second group lens 72 is at the point FP21.
The third group lens 73 is driven by a certain amount δ from δ to point F P 2141, and then the third group lens 73 is moved to point FP3! Kara point F P
Move to 3i+I, F P 2++1 becomes F P 2i+
2, FP 3i+I sequentially goes to FP3++2, and the second
The lens group 72 moves by a certain amount, and the third group lens 73 moves by a certain amount.
The movement to the position corresponding to the position of the group lens 72 is repeated, and the lens is stopped at the positions indicated by FP2j and FP3j at the time when the operation is stopped.

FIG. 10 shows a second embodiment using the first embodiment and the conventional cam cylinder.
Drive current waveforms when driving the group lens 72 and the third group lens 73 are shown by solid lines and broken lines, respectively. Due to its structure, this embodiment has less mechanical power loss and less load due to the mass of the cam barrel than when using a cam barrel, and in addition, the lens mass to be moved is driven in a time-divided manner. It can be seen that the peak current during acceleration is significantly lower than when time division is not performed. Therefore, it is possible to reduce large currents that particularly damage the power supply, and there is an effect that the burden on the power supply is reduced.

Further, in the first embodiment, only one drive circuit is required to drive the plurality of linear ultrasonic motors, and the circuit scale can be kept small. In addition, even though the lens groups are driven independently, there is no risk of the lens groups dynamically interfering with each other even if their movement ranges overlap. Furthermore, operations while looking through the finder do not cause unpleasant blurring, and time-divisional driving of multiple lens groups produces a remarkable effect that can be used for power focusing and zooming of a TTL camera.

In the AF operation of the first embodiment, the lens group is driven in a time-division manner to a predetermined position, similarly to power focusing, based on the lens group extension amount outputted by a known method. Therefore, it goes without saying that it has the above effects.

Next, a second example will be described. This example is
Although the configuration is almost the same as that of the embodiment, the second group lens 72 is moved by a certain amount and the third group lens 7 is adjusted to its stopped position.
The first position was calculated by calculation and was driven alternately.
Unlike the embodiment, the positions of the second group lens 72 and the third group lens 73 are stored in the ROM 56 in sets for various sufficiently detailed focus states, and Group lens 72 and third group lens 73
Power focusing is performed by referring to and driving a set of positions in order.

That is, FP2i and F P 3 i shown in FIG.
Values corresponding to the points sF P 2i+I and F P 3i+l... are stored as a set, and step FQ in FIG.
, the calculation using the formula F10 changes to referencing the ROM56,
Also, during high-speed driving, for example, two adjacent points are skipped, (
F P 21. F P 3i) to (F P 2i
+3. It is only necessary to select values that will become the target position intermittently, such as F P 3i+3).

FIG. 11 shows a flowchart of power focusing in the second embodiment. After determining high speed or low speed in steps F3 and F6, the number of data skips is determined. In this case, "1" indicates that an adjacent point where the focal position changes in the feeding direction is taken as the target position, and "3" indicates that two points are skipped and the third point is taken. In addition, minus (
-) is the renormalization direction. Based on the above data skip number, in step F9', the second group lenses 72 and 3
A set of target position data for the group lens 73 is read from the ROM 56. The rest is the same as in the first embodiment and is given the same reference numeral.

In the second embodiment, since the number of calculations is reduced, the processing speed of the calculation control section 57 is improved, and it is also advantageous to change the interval between the target positions according to the absolute distance depending on the degree of image deterioration. This also has the effect of more effectively suppressing image deterioration during operation.

Next, a third example will be described. Figure 14 shows the third
It is a figure showing the movement of each lens group of the zoom lens of an example. As shown in Figure 14, when the focal length is changed from wide to telephoto by zooming, the first lens group
The lens group and the third group lens are each moved to an edge relative to the focal plane by different amounts of movement (the solid line in the figure indicates the position of the final surface of each lens when focusing is at infinity). Furthermore, during wide, standard, and telephoto focusing, the first group lens and the second group lens are extended from infinity to close range as shown by the broken line in FIG. 14, and the amount of focusing extension differs depending on each focal length. It is difficult to make a zoom lens with such lens movement using a conventional frame structure using a cam or the like.

Therefore, in the third embodiment, a frame configuration as shown in FIG. 12 is adopted. That is, the first group lens 101, the second group lens 102, and the first group lens 101 are fixedly held by the 1-groove frame 104, the 2-groove frame 105, and the 3-groove frame 106, respectively. 1 groove frame 104.2 groove frame 105.3 groove frame 106,
They are guided by bearings 108, 109° 110 arranged on the inner periphery of the fixed frame 107 and the inner periphery of the one-groove frame 104, respectively, so that they can move inside the fixed frame 107 only in the optical axis direction. Vibrating bodies 111, 11 arranged in one groove frame 104 at substantially symmetrical positions with respect to the optical axis of the bearing.
2,113 in the direction of the bearing.

Therefore, 1 groove frame 104.2 groove frame 105.3 groove frame 10
6 is connected to the fixed frame 107 by each bearing 108, 109, 110 and each vibrating body 111, 112, 113,
There is no deviation in the position in the optical axis direction or the center of the optical axis, and it is positioned without any wobbling.

Note that the details of the attachment of the vibrating body and the operation of the linear ultrasonic motor are the same as those described in the eleventh embodiment, and will therefore be omitted.

Next, the configuration of the electric circuit of the third embodiment will be explained with reference to FIG. In the figure, 521 to 523 are linear ultrasonic motors corresponding to the vibrating bodies 111 to 113 in FIG. 12, respectively, and 511 to 5]3 are ultrasonic motors 52
This is an encoder that is driven by 3 and detects the movement of the frame. Encoder 51. ~513 consists of a scale written in two rows with graduated scales shifted in phase at equal intervals, and its reading section.On the scale, another row of scale marks is also written that indicates the end position which is the reference value. ing.

In this case, the scale is disposed on the fixed frame 071, and the reading section is disposed on the one-groove frame 104 to the three-groove frame 106, respectively. When the reading section moves relative to the scale, a pulse is generated and output at the position where the scale passes.

531 to 533 are direction detection circuits, and the encoder 511
The moving direction is detected from the phase inversion of two series of pulses with different phases generated by 513.

55 and 553 are up/down counters that count encoder pulses from the end position; 54 is an arithmetic control unit 5;
Vibrating bodies 111 to 113 based on drive control signals from 7
59 is a switching circuit that switches the pulses generated by the drive circuit 54 to one of the ultrasonic motors 521 to 523.

Note that the drive circuit 54, ROM 56, arithmetic control section 57, and switching circuit 59 are substantially the same as those in the first embodiment, so their explanations will be omitted.

58 is an AF module using TTL position difference detection method; 6
01 is a button-based focusing operation input unit for manually performing focusing, and 603 is a button-based zooming operation input unit for zooming.

FIG. 13 is an overview diagram of the zoom lens and camera in the third embodiment. That is, the camera body 91 includes a release button 92 that can output signals for first release when pressed halfway and second release when pressed fully, a finder 93 that uses a pentaprism to determine the angle of view, and a light path to the finder 93. A quick-return type main mirror 94, and a sub-mirror 95 attached to the main mirror 94 that guides light from the center to the AF module 58 at the bottom of the body.
, and an AF module 58 are provided. Also,
The lens 96 side is provided with a focusing operation input section 601 and a zooming operation input section 603 that can output half-press and full-press signals used during manual focusing (power focusing).

Next, the zooming operation according to the third embodiment will be explained based on the flowchart shown in FIG. In this embodiment, the operation of the photomos relay is omitted because it is simple, but it is the same as in the first and second embodiments. First, when the zooming operation input unit 603 is operated, an integer i indicating the zoom state and an integer k indicating the focus state stored at the time of the previous operation stop are read out (FIOI). Next, when the tele button of the zooming operation input section 603 is pressed,
i=i+1 (F102). When the wide button of the zooming operation input section 603 is pressed,
'-1-1, but since the subsequent operations are the same, the following description will be made assuming that the tele button is pressed.

The ROM 56 stores in advance the extension amount (distance, infinity) of each lens group by zooming from the initial position (wide, infinity position) Pli-P31, PI in that zooming state, and the extension amount Qli by focusing from 1-P3i. (k) to Q3 [(k) are respectively stored (see FIGS. 17 and 18).

This value is calculated from the zooming state i' and the focus state k.
Read based on. Then, from this read value, a value corresponding to the target position is determined as P'1! '(k)-pH'
+Q11' (k) P'21' (k)
-P21'+021' (k) P'3i'
(k) -P3i'+Q31' Calculate each using (k) (F 103).

Next, start driving the first group lens 101.F104
), the counter 55 . You can judge by reading the output of F105
), P'I+' (k), the driving of the first group lens 101 is stopped (F2O3).

Similarly, the second lens group 102 and the third lens group 103 are moved (F107 to F112), and it is determined whether the zoom operation is still being performed (F113). If the tele button is still pressed, the value of i' is incremented by one and the process returns to step F103; if the process has ended, the value of i' is written to the memory as a value indicating the final zoom state (F115),
Finish the operation.

As shown in FIGS. 17 and 18, Plf~pat
, Qll(k) to Q31(k) are set at a resolution that does not cause discomfort during operation as described above, so it is possible to reduce the current and simplify the circuit as described in the first embodiment. After achieving this, zooming operations can be performed without discomfort while looking through the viewfinder.

Next, the manual focusing operation will be explained with reference to the flowchart shown in FIG. 19. Focusing is so-called power focusing, in which manual focusing is performed electrically. Power focusing is almost the same as zooming, and the focusing operation input section 60. When you press the button,
Read out zoom state 1 and focus state k (F121)
When the feed button is pressed, set +1 to '-', and when the carry-in button is pressed, set -1 to '-. Thereafter, the target position is calculated in the same way as for zooming, the first group lens 101 is driven and the second group lens 102 is driven alternately, and when the focus operation is completed, the final focus state is written and the process ends (F123~ F1
32). An example of the operation during feeding is shown in FIG. 20.

In addition to the above, the autofocus operation in this embodiment will be explained with reference to the flowchart shown in FIG. 21. First, when the release button 92 is pressed halfway, a focus detection operation is started (F141), and a defocus amount is calculated from the output (F142). Next, read out the number i representing the initial zoom state and the number k representing the focus state stored in the previous operation (F143), read out the feed amount conversion coefficient K corresponding to these values from the memory, and, for example, △
The first group lens 101 and the second group lens 102 are
Calculate the feeding amount (F144). Then, the first group lens 101 and the second group lens 102 are extended in the same manner as power focusing to the final position determined from the above-mentioned extension amount (F145 to F153), and the focus is detected again (F15
4) If in focus (F155), store the zoom state and focus state and end the process.F156) If not in focus, return to step F142 again.

As described above, in the third embodiment, the number of zoom states,
Since the number of focus states is determined and the position of each lens group corresponding to that value is stored two-dimensionally, even zoom lenses with complicated movement of each lens group can be easily changed from any state. It is possible to realize a lens and a camera that can support zooming and power focusing and have the effects described in the second embodiment.

Next, a fourth example will be described. The configuration of this embodiment is similar to that of the third embodiment, but the buttons of the focusing operation input section 601 and the zooming operation input section 603 are two-stage switches, and the electric circuit is
As shown in the figure, the drive circuit and switching circuit are 541.5
It is composed of two each of 4□ and 59°59□, and the switching circuit is different in that it is slightly more complicated as shown in FIG.

First, focusing and zooming will be explained. These operations may be roughly fast or detailed and slow.

In this embodiment, if you want to move the lens quickly, that is, if you press the operation button to the second step, step F102 in FIG. F114 or step F in Figure 19
122. In F131, the plus number is "1"
For example, change it to "3" instead. This also allows for faster operation.

Next, a method of moving the lens will be explained. When the drive circuits are sequentially switched and driven as in the second embodiment, acceleration and stopping are repeated alternately, and the body and lens may be accompanied by vibrations. At this time, for example, the drive circuit 54.
When you finish driving the first group lens 101 and then try to drive the second group lens 102, the first group lens 101
If the drive of the second lens group 102 is started at the same time as the second lens group 102 stops, shocks caused by acceleration and deceleration cancel each other out, and vibrations are reduced. Therefore, before the first group lens 101 stops, the drive circuit 522 of the second group lens 102
42 is connected so that a drive start signal is given to the drive circuit 542 following the stop signal of the drive circuit 54□.

Although this embodiment requires two sets of drive circuits, it suffices with two sets of drive circuits no matter how many lens groups there are to be driven, and also has the effect of suppressing vibrations during drive.

Note that the focusing operation input section and the zooming operation input section of this embodiment are based on, for example, Japanese Patent Application Laid-Open No. 6B-17711.
It is more effective to change the driving speed in multiple stages using an electronic dial as shown in No. 8.

[Effects of the Invention] As detailed above, according to the lens driving device of the present invention,
Because the structure does not use a cam tube like in the past, complex lens movements such as those with inflection points are possible, and a compact lens can be realized. In addition, by temporally dividing driving of multiple lens groups, which is impossible with a method that guarantees the mutual position of the lens groups when the cams of the cam tube are filled, it is possible to reduce the current when driving the lenses, and the number of drive circuits can be reduced to one or two. can be kept to a minimum. moreover,
It has the remarkable effect that there is little distortion of the positional relationship while driving the lenses, it can also be used for zooming and focusing of TTL cameras, and there is no risk of mechanical mutual interference between the lens groups.

[Brief explanation of the drawing]

1 to 10 are for explaining the first embodiment of the present invention. FIG. 1 is a block diagram showing an electric circuit, and FIG. 2 is a sectional view of a zoom lens showing the lens configuration and frame configuration. , Figure 3 is an overview of the zoom lens and camera, Figures 4 and 5 are configuration diagrams showing details of the linear ultrasonic motor, and Figure 6 is a diagram of each lens group relative to the focus position based on infinity. A graph showing the amount of movement, FIG. 7 is a configuration diagram showing the drive circuit and switching circuit in detail, FIG. 8 is a flowchart explaining the power focusing operation, and FIG. 9 is a graph showing the amount of movement of the second group lens versus the third group lens. FIG. 10 is a graph showing the driving current characteristics of the lens group. FIG. 11 is a flowchart explaining the power focusing operation of the second embodiment of the present invention. FIGS. This is for explaining the third embodiment of the invention. FIG. 12 is a cross-sectional view of a zoom lens showing the lens configuration and frame configuration, FIG. 13 is an overview of the zoom lens and camera, and FIG. 14 is a diagram showing the focal length Figure 15 is a diagram showing the position of each lens group. Figure 15 is a block diagram showing the electric circuit.
Figure 6 is a flowchart explaining the zooming operation, the first
Fig. 7 is a graph showing the amount of extension of each lens group with respect to the zoom state, Fig. 18 is a graph showing the amount of focus extension with respect to the zoom state, Fig. 19 is a flowchart explaining the manual war focusing operation, and Fig. 20. 21 is a flowchart illustrating an autofocus operation, and FIG. 22 is a detailed configuration diagram showing a drive circuit and a switching circuit in a fourth embodiment of the present invention. 511-513...Encoder, 521-523...
・Linear type ultrasonic motor, 531 to 533... Direction detection circuit, 54... Drive circuit, 55, to 553... Up/down counter, 56... ROM, 57... Arithmetic control unit, 58 ...AF module, 59...switching circuit, 60,...focusing operation input section, 602
...AF/PF switching section, 603...Zooming operation input section, 71...First group lens, 72...Second group lens, 73...Third group lens, 74...Third group lens 4th group lens, 75...Fixed frame, 76...2nd group frame, 77...
3rd group frame, 78.79...Bearing, 80.81...
- Vibrating body, 92... Release button. Figure 2 Figure 1 Figure 3 Figure 13b (A) (B) Figure Drive start time Position of each lens Figure 14 Figure (b) Figure 16 (a) Figure 16 (b) Figure 17 Figure 19 (a) Figure 20 Figure 19 (b) Figure 21 (a) F149 F156 Figure 21 (b)

Claims (1)

[Claims] A plurality of lens groups movable in the optical axis direction, a plurality of drive means for driving the plurality of lens groups, and a drive control means for generating a drive signal for driving the drive means. a switching means for switching and transmitting a drive signal generated from the drive control means to one of the plurality of drive means; a drive target position output means for outputting a drive target position of each of the plurality of lens groups; a first control means that outputs a control signal for controlling the switching operation of the switching means in order to sequentially drive each of the plurality of lens groups by a minute amount; A lens driving device comprising: second control means for repeatedly outputting the control signal until the drive target position is reached.