JP2832022B2 - Camera and lens unit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera suitable for use in a camera system having an automatic focus adjustment (hereinafter, referred to as AF) device for the camera.

(Background Art) In recent years, the development of video equipment such as cameras has been remarkable, and video cameras and the like generally provided with an automatic focus adjustment device, an automatic exposure adjustment device, and the like.

FIG. 12 shows a so-called passive AF device that detects a focus state of an optical system from a video signal obtained by photoelectrically converting a subject image formed through the optical system and performs automatic focusing (AF). FIG. 4 is a block diagram showing an example of the above.

In FIG. 12, reference numeral 101 denotes a first lens group 102 for focus adjustment.
Is a second lens group for zooming, 103 is a third lens group for correcting a change in focal position due to zooming, 105 is a fourth lens group which is an imaging system, and 120 is Imaging surface, 121 is 12
An amplifier that amplifies the output signal of 0, 122 is a high-pass filter, 123 is an AF control microcomputer (hereinafter referred to as AF microcomputer) that performs AF control and outputs a motor drive command;
110 is a drive device 10 described later according to the instruction of the AF microcomputer 123.
7, a driver for supplying energy to the driver 7, a driver 107 controlled by the driver 110 to move the focus adjustment lens group 101, a DB for transmitting a command from the AF microcomputer 123, and a M for a camera unit. And a boundary line indicating the boundary between the lens unit and the lens unit.

In a passive AF system as shown in FIG. 12, first, an image passed through an optical system on an imaging surface 120 is converted into an electric signal. This electric signal is amplified by the amplifier 121 and input to the high-pass filter 122. The high-pass filter 122 extracts only high-frequency components related to the degree of focus of the video signal, and inputs the extracted high-frequency components to the AF microcomputer 123. It is generally known that the level of a high-frequency component of a video signal increases as the focus approaches the focus by adjusting the optical system, as shown in FIG. That is, the level (vertical axis) of the high-frequency component of the video signal changes with the movement of the focusing lens (horizontal axis), and reaches a maximum value at a position where focusing is performed on the subject distance. Therefore, AF microcomputer 123
Then, if a lens driving command is output to the driver 110 via the transmission path DB so that the output of the high-pass filter 122 becomes maximum, AF becomes possible. The driver 110 generates energy sufficient to rotate the motor 107 based on a signal from the AF microcomputer 123, and drives the motor 107.

In such an AF system configuration, it is necessary to generate a drive waveform of the motor 107 in the AF microcomputer 123. As the motor drive signal, a method of controlling the speed by an applied voltage or a periodic signal having a drive waveform, for example, DC
Turn ON with duty drive waveform for motor
Although there is a method of controlling the speed by exciting the motor only during the period, the former cannot reduce the torque at low speed because the applied voltage must be reduced at low speed. Therefore, the latter method is generally used. When such a duty control driving method is adopted, the motor control is performed in the program for performing the AF control, and thus the cycle of the drive waveform is synchronized with the repetition cycle of the program of the AF microcomputer 123. Conventionally, an AF system using this drive waveform has been used in almost all models.

In recent years, many proposals have been made for an interchangeable lens system in which the lens unit and the camera unit are separated at the boundary M in FIG. 12 while maintaining the basics of the AF system as shown in FIG. In this type of device, since the lens side is normally controlled by control information from the camera body, motor drive is also controlled by AF control, that is, in a normal video camera, control is performed at a field cycle or a cycle that is an integral multiple of the field cycle. ing.

(Problems to be Solved by the Invention) However, the above-described system has problems as described below.

FIG. 14 shows a case where the program repetition period of the AF microcomputer 123 is equal to the vertical synchronization period (50 Hz) of the PAL system, which is one of the television systems, and the period of the drive signal waveform is equal to the program repetition synchronization of the AF microcomputer 123. FIG. 6 shows a relationship between switching timings of a vertical synchronizing signal of the video signal of FIG.
Vertical sync signal of AL system, 203 is NTSC vertical sync signal, 140
1 is a motor drive waveform.

As is apparent from FIG. 14, reference numeral 1401 denotes a pulse waveform generated in synchronization with the vertical synchronization signal 201 of the PAL system. As described in the conventional example, the period of 1401 is governed by the repetition period of the program.
If it is used as it is for NTSC, the signal synchronized with the NTSC vertical synchronization signal 203 in FIG.
The signal has a shorter cycle and ON time than 01. That is, the cycle and the ON time of the motor drive waveform 1401 are originally determined according to the characteristics of the motor 107 in the lens unit. Therefore, when the microcomputer 123 on the camera side generates the drive waveform as described above in the interchangeable lens system, not only the type of lens is limited by the television system, but also every cycle and ON time output from the camera side. Motors must be designed to drive properly.

Also, if the AF program repetition cycle is not limited, a correct waveform will not be generated, so that the degree of freedom in designing the entire system will be significantly impaired, and the combination which is the original purpose of the interchangeable lens will not be possible. This results in a significant cost increase.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above-mentioned problems, and the feature of the present invention is to drive a driving unit that changes the state of an optical system. A lens unit comprising: an actuator; and a drive unit for driving the actuator based on a drive control command supplied at a predetermined cycle from a control unit on the camera side, wherein the drive unit drives the actuator at a timing. Is set at a timing different from the timing at which the control means supplies the drive control command to the drive means.

That is, the cycle of the drive signal of the actuator is controlled asynchronously with the program repetition cycle of the control means, and the control of the operation of the actuator can be freely selected regardless of the operation conditions of the control means.

Another feature of the present invention is that an actuator for driving a drive unit that changes the state of the optical system, a drive unit that supplies a drive signal to the actuator at a predetermined cycle, and a drive control command to the drive unit A control unit for supplying a driving control command for changing the driving state when the driving state such as the driving direction or the driving speed of the actuator is changed. And the driving unit is configured to change a driving state of the actuator in accordance with the driving control command, prior to an end of a cycle of the driving signal.

Another feature of the present invention is that the actuator is driven based on a drive control command supplied at a predetermined cycle from a control unit on the camera side, for driving a drive unit that changes the state of the optical system. A driving unit that performs a driving control command indicating that a driving state such as a driving direction or a driving speed of the actuator is changed from the control unit. In the lens unit configured to change the driving state of the actuator prior to the end of the cycle.

As a result, control responsiveness can be improved.

Further, another feature of the present invention is an actuator for driving a driving unit that changes the state of the optical system, and a driving unit that drives the actuator based on a driving control command supplied from a control unit on the camera side. Wherein the driving unit receives the drive control command from the control unit, and if the command is to change the drive direction of the actuator, the drive unit Lens unit provided with a means for braking for a predetermined time prior to the reversal of.

As a result, smooth lens driving can be realized.

Another feature of the present invention is that an actuator for driving a drive unit that changes the state of the optical system and a pulse drive of the actuator based on a control signal supplied at a predetermined cycle from control means on the camera side. Driving means, wherein the driving means is configured to asynchronously control a cycle of a driving pulse at which the driving means drives the actuator and a cycle at which the control signal is supplied from the control means. In the lens unit.

Another feature of the present invention is an actuator for driving a driving unit that changes the state of the optical system, a driving unit that drives the actuator in pulses, and a control that supplies a control signal to the driving unit at a predetermined cycle. A driving pulse, wherein the driving means drives the actuator,
There is a camera in which the cycle of supplying the control signal to the driving means by the control means is asynchronous.

Thereby, the control of the operation of the actuator of the optical system can be freely selected regardless of the operation condition of the control means, and the operation state of the lens unit can be changed regardless of the control system of the camera.
Constant characteristics can be maintained.

First Embodiment Hereinafter, a camera according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a camera according to the present invention. In the figure, components having the same functions as those already described with reference to FIG. 12 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 1, 100A indicates a lens unit of the interchangeable lens system, 100B indicates a camera unit of the interchangeable lens system, and the lens unit 100A is detachable from the camera unit 100B. Reference numeral 104 denotes an aperture, and reference numeral 106 denotes a cam ring in which a cam groove is formed so as to interlock the lens groups 102 and 103 while maintaining a predetermined positional relationship. 107, 108 and 109 are respectively a lens group 101 and a cam ring 10
6, a motor for driving the aperture 104, 110, 111, 112 are drivers for driving the motors 107, 108, 109, respectively, 113,
Reference numerals 114 and 115 denote a lens group 101, a cam ring 106, and an aperture 104, respectively.
Encoder that converts the displacement of the
6 is the driver 110, 11 according to the driving command from the camera side.
1, a lens microcomputer for outputting a drive signal to 112, a transmission line 117 for transmitting a drive command to the lens microcomputer 116, 118
Denotes a lens-side connector, 119 denotes a camera-side connector, and 124 denotes a transmission path for transmitting a drive command output from the camera-side microcomputer 123 to the connector.

A subject image projected on an imaging surface 120 of an imaging device such as a CCD via the lens groups 101, 102, 103, the aperture 104, and the lens group 105 is converted into an electric signal in the same manner as in the related art, and is converted into an electric signal.
1. Only the high-frequency component is input to the microcomputer 123 via the high-pass filter 122. As described in the conventional example, the microcomputer 123 outputs a lens driving command to the lens microcomputer 116 via the transmission path 124, the connector 119, the connector 118, and the transmission path 117 so that the level of the high-frequency component is maximized. The lens microcomputer 116 moves the focus adjustment-like lens 101 in accordance with the drive command in order to move the lens 101.
A drive signal is output to the driver 110.

FIG. 202 shows a drive waveform output from the lens microcomputer 116 to the driver 110 at this time. In FIG. 2, waveforms 201 and 203 are PAL signals as described in FIG.
5 is a vertical synchronizing signal waveform of a system television signal and an NTSC system television signal. Reference numeral 202 denotes a motor drive signal waveform according to the present invention.

As in FIG. 14, the program execution repetition cycle of the camera-side microcomputer 123 is such that the motor drive waveform 202 does not synchronize with either the PAL vertical synchronization signal 201 or the NTSC vertical synchronization signal 203 even if the motor drive waveform 202 is synchronized with the vertical synchronization signal. To change
Change the motor speed. A drive signal waveform that is not synchronized with the program execution repetition cycle of the microcomputer 123, such as the motor drive waveform 202, is supplied to the microcomputer provided in the lens.
If generated by 116, the design of the microcomputer 123 and the AF system in the camera 100B, and even the difference in the television system, allows the free design of the lens unit without adjusting the characteristics of the motor in the lens to these. . In other words, the relationship between the predetermined speed and the drive waveform is determined between the lens microcomputer 116 and the motor in the lens. For example, if a table is created in the microcomputer, the speed information and the drive direction are obtained from the camera microcomputer 123. Only by receiving the information, it is possible to obtain the lens driving performance as instructed by the microcomputer 123. As a means for generating the actual motor drive signal waveform 202, for example, a clock used for the microcomputer 116 or a program execution repetition cycle may be set completely independently of the microcomputer 123.

(Second Embodiment) FIG. 3 shows a configuration diagram of a second embodiment of the present invention. Components having the same functions as those of the components described so far are denoted by the same reference numerals. It is attached. In FIG. 3, reference numerals 301 and 302 denote motors for moving the lens groups 102 and 309, respectively. In particular, the motor 302 is a step motor. 303 and 304 are drivers for driving the motors 301 and 302, respectively, 305 and 306 are encoders for converting the displacements of the lens groups 102 and 309 into electric signals and detecting them, 307 is a lens microcomputer for control, and 308 is a fixed microcomputer. The first lens group, lens group 309, is a third lens group that adjusts the position of the focal point that changes with the displacement of the lens group 102, and also performs focus adjustment when the lens group 102 is stopped. Reference numeral 300A denotes a lens unit of the present lens system.

As in the first embodiment, the image projected on the lens 120 through the optical system is converted into an electric signal, and the focusing lens is moved from the camera microcomputer 123 to the lens microcomputer 307 so that the level of the high-frequency component is maximized. A driving command is transmitted.

In the lens unit 300A, since the lens group 309 has a focus adjusting function, the lens microcomputer 307 is connected to the camera microcomputer 1.
Driver 30 according to the focusing drive instruction from 23
Output drive signal to 4.

When the focus adjustment is to be performed by a lens unit other than the first lens unit for the lens unit 300A, the correction trajectory of the lens unit 309 is generally complicated by zooming by moving the lens unit 102. Therefore, it is necessary to control the lens group 309 with high accuracy. For this purpose, a stepping motor or the like may be used as the driving motor 302 as described in this embodiment.

FIG. 4 shows a motor drive waveform output from the lens microcomputer 307 when a step motor is used as a drive motor of the lens group 309 as a focusing lens, as shown in FIG. Waveforms equivalent to those in FIG. 2 are given the same numbers.

In FIG. 4, reference numerals 401, 402, 403, and 404 denote drive waveforms at respective terminals of the two-phase excitation step motor. First
Similarly to the embodiment, by making the clock of the lens side microcomputer 307 and the program execution repetition cycle independent of the camera side microcomputer 123, the motor drive waveform can be any of the PAL system vertical synchronization signal 201 and the NTSC system vertical synchronization signal 203. The lens microcomputer 307 can independently generate a drive signal waveform based only on the speed information and the drive direction information from the camera microcomputer 123 without synchronization. In particular,
A table of a plurality of motor drive signal waveform cycles corresponding to control commands transmitted from the camera side is formed in the lens microcomputer, and a drive waveform corresponding to the command is selected and supplied to the motor driver. What should I do?

Third Embodiment FIG. 5 shows a third embodiment of the present invention, and is a flowchart of a control program in the lens microcomputer 116 or 307. The configuration of each component in this embodiment is the first embodiment. And is equivalent to the second embodiment.

The present embodiment relates to the case where the first or second embodiment is executed, particularly when a command for reversing the driving direction of the focusing lens is issued from the microcomputer 123 on the camera side.

In FIG. 5, reference numeral 501 denotes a step indicating the start of execution of a program; 502, a step for confirming the state of a flag indicating that a timer in a microcomputer for generating a pulse waveform of a motor drive signal has finished counting; Is a step of stopping the timer, 504 is a step of clearing the count value of the timer, 505 is a step of newly setting a count end value of the timer, and 506 is a motor drive direction command from 123 to determine whether the drive signal is positive or negative. 507 is a step for starting the timer count, 508 is a step for determining whether the timer count value has reached 505, 509 is a step for turning on the count end flag determined in 502, and 510 is a count. A step for turning off the end flag, a step 511 for continuing the counting of the timer, and a step 512 for the state of the timer. Step for generating a periodically pulse equal, 513 outputs the pulse generated by 512 to the motor drive step, 514
Is a step for receiving a speed command from the microcomputer 123 on the camera side, 515 is a step for receiving a direction command from the microcomputer 123 on the camera side, and 516 is a step in which the direction command received at 515 is reversed with respect to the current driving direction of the motor. Step 517 is to determine whether or not the speed command has changed.

When the program starts in 501, it is determined in 502 whether a count end flag indicating whether or not the timer has finished counting is ON. If the count end flag is ON, it means that the generation of the motor drive waveform has been completed for one cycle.
To reset the timer to the start value. Then, at 505, a new timer count end value determined by the speed command transmitted from the camera microcomputer 123, that is, a time until a motor drive waveform for one cycle is generated is set.
Further, at 506, the positive / negative of the motor driving waveform for determining the driving direction of the motor is determined from the direction command from the camera microcomputer 123, and at 507, the timer starts counting.

On the other hand, if it is determined in 502 that the count end flag is OFF, the count of the timer is not restarted, and
In step 515, only the reception of the drive command from the camera microcomputer 123 is accepted. Then, at 516, it is determined whether the latest driving direction command is the same as the current motor driving direction or the reverse direction. If the current direction is the reverse direction, the process immediately jumps to 503 to recreate the motor driving pulse.

Further, even if it is determined in 516 that the direction is the same, if it is determined in 517 that the speed command is different, jump to 503 similarly.

After the timer count restarts in 507, check in 508 whether the timer count value has reached the value of the timer operation time set in 505, and if so, turn on the count end flag in 509 and return to 502 The same operation as the above-described control operation is repeated. If the counting has not been completed, the counting is continued at 511 to turn off the counting end flag at 510 and generate a drive signal according to the instruction.
Then, a pulse waveform for driving the motor is generated at 512 and supplied to the motor at 513 to drive it.

FIG. 6 shows a drive waveform when this embodiment is applied to the duty drive of the DC motor. In FIG. 6, reference numeral 601 denotes a motor drive waveform generated according to the present embodiment;
In the control algorithm of FIG. 5, it is assumed that the step of determining the motor reversal at 516 is removed, and even if the reverse command is issued from the microcomputer 123 on the camera side, the drive waveform generation state is maintained until the timer count is completed. Shows the rising timing of the first pulse after the inversion command when controlling so as not to change. Reference numeral 603 denotes the camera microcomputer 1 when the program execution cycle of the camera microcomputer 123 is synchronized with the PAL vertical synchronization signal 201.
This is the output timing of the focusing motor drive command issued from 23. In the figure, it is assumed that there is an inversion at a and a speed change at b. 604 is 517 in FIG.
In other words, the first pulse rising timing after the command is executed in a case where the control step is not changed until the counting of the timer is completed even if the speed change command is issued. It is.

As is apparent from FIG. 6, if there is a change in the driving command of the focusing motor, a step 51 for detecting this change is performed.
By providing 6, 517, it becomes possible to drive the lens in response to an instruction from the camera microcomputer 123. This not only improves the response speed but also prevents a malfunction of the microcomputer 123 such as outputting another command erroneously because the change command is issued but not changed.

In the present embodiment, for example, even if commands for speed change and direction reversal are issued at the same time, the algorithm is such that control is restarted from step 503, so that the rotation direction and rotation speed of the motor can be changed at the same time. The thing is clear.

FIG. 7 is a time chart when the present embodiment is applied to a step motor. Reference numerals 701, 702, 703, and 704 denote motor drive waveforms generated by the application of the present embodiment, and dotted lines 705, 706, 707, and 708 denote direction reversals and speed changes of 516 and 517 in the control flow in FIG. It is a motor drive waveform when a program without the inversion discrimination step is used. It can be seen that even if a command to change the speed and direction is issued, the drive signal waveform is not changed until the drive cycle ends, so that the timing is delayed. When the present embodiment is applied, even if the direction reversal and the speed change command are issued at 603 at the same time, the direction reversal and the speed change can be performed immediately.

(Fourth Embodiment) FIG. 8 is a flowchart of a program in a lens microcomputer according to a fourth embodiment of the present invention, and the configuration of a system for realizing this program is the same as in FIGS. 1 and 3. . Note that the same reference numerals are given to programs having functions equivalent to those in the control flowchart of FIG. In this embodiment, the response characteristics when the driving direction of the motor is reversed are further improved.

In FIG. 8, reference numeral 801 denotes a block for declaring the start of a program. In step 516, a step 516 for judging the presence or absence of a motor drive direction reversal command, a brake is applied to the motor when a motor drive direction judgment command is issued. Step 803 for operating a timer that counts the time to apply, 803 is a step for short-circuiting the motor terminals and applying a brake to the motor, 804
Is a step for confirming whether or not the brake counter has finished counting. For other steps,
The description is omitted because it is the same as FIG.

In the third embodiment, a description has been given of the means for switching the polarity of the motor drive signal and the phase of any step motor when the focusing lens inversion command is issued from the camera microcomputer 123. According to the third embodiment, the drive signal is immediately inverted, but the time until the lens actually stops moving and starts the inversion operation is not clear.
That is, since the speed of the lens before the inversion, the inertia of the lens, the cycle and the duty ratio of the drive signal after the inversion vary, for example, even if the camera issues a reversal command from the microcomputer, the lens does not immediately respond and does not reverse. Therefore, the camera microcomputer issues a command of a higher speed, so the lens starts reversing for the first time, but this time the speed is too high and it goes over the correct position, and so-called hunting operation that outputs the reversal command There is a danger of doing

Therefore, in order to compensate for this, when the lens side microcomputer receives the inversion command, instead of switching the polarity or phase of the drive signal immediately, the brake is applied by an operation such as short-circuiting the motor terminal, and the motor is started. In this embodiment, the operation is stopped and then reversed.

In this embodiment, the flow of the program when the count end flag is ON in step 804 is the same as that in the embodiment of FIG. Also, even if the count end flag is OFF,
If the drive command from the microcomputer 123 does not indicate inversion, the program flow is the same as that of the embodiment of FIG.

In FIG. 8, when it is determined in step 516 that an inversion command has been received, in step 802, a timer for applying a brake for a predetermined time starts counting. Here, it is possible to prepare a plurality of types of the braking time depending on the moving speed of the lens and the like, and to select a time corresponding to the speed.
That is, a table in which the braking time and the speed correspond to each other may be created in the microcomputer in advance. In step 803, the motor terminal is short-circuited and the brake is applied. In step 804, it is determined whether or not the braking time has ended.
Return to and continue to brake. If it is determined in step 804 that the braking time has ended, the process returns to step 503 to start the reverse rotation operation.

FIG. 9 is a timing chart for the drive signal of the embodiment of FIG. 8, in which 901 indicates a drive waveform generated by the program of FIG. 8, and 902 indicates a braking period. As is apparent from FIG. 9, when the reversal command is issued at the time of 603, the brake is immediately applied, and after a predetermined braking period is completed, a drive signal in the reverse direction is output.

Although the braking period is set by a timer in FIG. 8, it is also possible to use a position encoder shown in FIGS. 1 and 3 to stop the lens by the output of the position encoder. There is also a means of continuing to apply the brake until the confirmation is made, and outputting an inversion signal when the brake is stopped.

As described above, in the third and fourth embodiments, at the time of inversion, 503, 504, 50
In steps 5 and 506, the count is restarted after the timer starts counting. However, any drive system that can reduce the first pulse width after inversion of the drive signal can be omitted.

(Fifth Embodiment) FIGS. 10 and 11 are flowcharts of a program according to a fifth embodiment of the present invention. FIG. 10 shows a program in the camera microcomputer, and FIG. 11 shows a program in the lens microcomputer. . No.
In FIG. 10, 1001 is a block for starting execution of a program, 1002 is a step for performing an operation for judging an in-focus state of an optical system, 1003 is a step for judging whether it is necessary to invert a focusing lens, 1004 is a program for turning on a flag (reversal flag) which is turned on when the lens needs to be reversed, 1005 is a program for turning off the reversal flag, 1006 is a focusing state discrimination step 1002 based on the result of the focusing state determination step 1002. A step 1007 for determining the speed and outputting to the lens side, a program 1007 for similarly determining the motor driving direction and outputting to the lens side, and a step 1008 for outputting an inversion flag to the lens side.

FIG. 11 is an extract of only the program in the case where the count end flag is OFF in the flowcharts of the programs in FIGS. 5 and 8, and the other operations are the same. In FIG. 11, reference numeral 1001 denotes a step for receiving an inversion flag, and reference numeral 1002 denotes a step for determining whether or not the inversion flag is ON. These two steps have been added.

In the present embodiment, the camera-side microcomputer attempts to determine the reversal performed by the lens-side microcomputer in the third and fourth embodiments.

In the microcomputer on the camera side, when execution of the program is started by 1001, it is determined whether the focusing motor should be moved in either direction to reach the top of the video signal level in 1002, and the top is moved away. Steps 1006 and 10 according to a pre-determined algorithm to make the focusing motor move faster and closer
Decide the speed and direction in 07. At this time, if it is determined in step 1003 that the driving direction is reversed, the inversion flag is turned on in step 1004, and if not, the inversion is performed in step 1005.
F. This inversion flag is transmitted to the lens microcomputer in step 1008. On the lens microcomputer side, the inversion flag is received in step 1101, the ON / OFF is determined in 1102, and if it is ON, the process immediately jumps to step 503 to switch the polarity (or phase) of the drive signal.

By doing so, the load on the program on the lens microcomputer side can be reduced, and the processing speed can be improved and the memory area can be reduced.

Although the above five embodiments have described the motors for moving the focusing lens, it is needless to say that these can be applied to all actuators of the lens unit including the zooming lens.

(Effects of the Invention) As described above, according to the present invention, the timing at which the drive unit drives the lens control actuator and the timing at which the control unit supplies the control command to the drive unit are asynchronous. Therefore, for example, in the AF operation of the camera, by synchronizing the drive signal waveform of the motor as the actuator with the program repetition cycle of the AF control microcomputer, the lens drive motor is independent of the operating conditions of the AF control microcomputer. Can be freely selected.

That is, by controlling the drive signal of the actuator for moving the lens in synchronization with the operation execution cycle of the circuit for performing the AF determination and control, regardless of the structure and operating conditions of the circuit for performing the AF determination and control, freely. Not only can the lens unit be designed, but also the motor can be driven correctly for the lens movement speed specified by the AF circuit.

Further, in the AF circuit, when an instruction to change the moving state of the lens is tried, if the change is made, the current lens operation is stopped and a means for resetting the moving condition is executed to execute the lens operation. Deterioration of AF performance due to the performance of the unit can be avoided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention, FIG. 2 is a motor drive signal waveform diagram in the first embodiment, FIG. 3 is a block diagram showing a second embodiment of the present invention, FIG. 4 is a waveform diagram of a motor drive signal according to the second embodiment. FIG. 5 is a control flowchart showing a third embodiment of the present invention. FIGS. 6 and 7 are motor drive signals according to the third embodiment. FIG. 8 is a control flowchart showing a fourth embodiment of the present invention. FIG. 9 is a motor drive signal waveform diagram of the fourth embodiment. FIGS. 10 and 11 are fifth diagrams of the present invention. FIG. 12 is a block diagram of a conventional camera, FIG. 13 is a diagram for explaining an AF control operation, and FIG. 14 is a waveform diagram of a motor drive signal in a conventional example.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-218268 (JP, A) JP-A-63-235882 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04N 5/225-5/232 G02B 7/08

Claims (7)

(57) [Claims] 1. An actuator for driving a drive unit that changes the state of an optical system, and a drive unit for driving the actuator based on a drive control command supplied at a predetermined cycle from a control unit on a camera side. A lens unit comprising: a lens, wherein a timing of driving the actuator of the driving unit is set to be different from a timing of supplying the driving control command from the control unit to the driving unit. unit. 2. An actuator for driving a drive unit that changes the state of an optical system, a drive unit that supplies a drive signal to the actuator at a predetermined cycle, and a control unit that supplies a drive control command to the drive unit. Wherein the control means, when changing the drive state such as the drive direction or drive speed of the actuator, supplies a drive control command for changing the drive state to the drive means, The camera, wherein the driving unit is configured to change a driving state of the actuator prior to an end of a cycle of the driving signal in accordance with the driving control command. 3. An actuator for driving a drive unit that changes the state of the optical system, and a drive unit for driving the actuator based on a drive control command supplied at a predetermined cycle from a control unit on the camera side. A lens unit comprising: a drive unit that, when receiving a drive control command from the control unit indicating a change in a drive state such as a drive direction or a drive speed of the actuator, ends the cycle of the drive signal. A lens unit configured to change a driving state of the actuator in priority to the lens unit. 4. A lens unit comprising: an actuator for driving a driving unit that changes the state of an optical system; and a driving unit for driving the actuator based on a driving control command supplied from a control unit on a camera side. When the drive unit receives the drive control command from the control unit, if the command is to change the drive direction of the actuator, prior to reversing the drive direction of the actuator, A lens unit comprising means for applying braking for a predetermined time. 5. An actuator for driving a driving unit that changes the state of an optical system, and a driving unit for pulse driving the actuator based on a control signal supplied at a predetermined cycle from a control unit on the camera side. Wherein the driving unit is configured to asynchronously control a period of a driving pulse at which the driving unit drives the actuator and a period of supplying the control signal from the control unit. Lens unit. 6. An actuator for driving a drive unit that changes the state of an optical system, a drive unit for pulse driving the actuator, and a control unit for supplying a control signal to the drive unit at a predetermined cycle. A camera, wherein a driving pulse for driving the actuator by the driving unit and a cycle for supplying a control signal to the driving unit by the control unit are asynchronous. 7. The apparatus according to claim 6, wherein the driving unit is a focus lens, and the control unit is configured to supply focus adjustment information to the driving unit in the cycle. Camera.