JPH11326739A - Lens driving controller and lens driving control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens driving controller and a lens driving control method by which torque required for driving a moving lens group can be outputted even at low temperature time when the output torque of a lens driving means for driving the moving lens group is lowered, and to provide an optical equipment using the same. SOLUTION: The optical equipment is provided with the moving lens groups 102 and 105 capable of moving in an optical axis direction, the lens driving means 118 and 120 moving the lens groups 102 and 105 at specified speed, a temperature detection means detecting ambient temperature, and driving control means 115 and 121 driving and controlling the driving means 118 and 120 based on temperature data obtained from the temperature detection means; and the control means 115 and 121 are constituted to change the driving condition of the lens groups 102 and 105 by the driving means 118 and 120 based on the temperature data obtained from the temperature detection means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens drive control apparatus and method for driving a moving lens group by a stepping motor and an optical apparatus using the same, and is suitable for an image pickup apparatus such as a video camera.

[0002]

2. Description of the Related Art Conventionally, in an imaging apparatus such as a camcorder or a monitoring camera, a lens system in which a zoom lens or a focus lens is driven by a pulse motor is generally used.

In an inner focus lens widely used as a lens system of this kind, a focus lens for correcting a change in a focal plane due to movement of a zoom lens when an image of an object at an arbitrary subject distance is taken while zooming. Since the focusing trajectory varies depending on the subject distance, it is necessary to accurately control the zoom lens position and the focus lens position.

If a pulse motor is used as a motor for driving a lens such as a zoom lens or a focus lens, the rotation angle with respect to the number of stepping pulses is constant. The position of the lens can be accurately detected by incrementing or decrementing the pulse and counting the number of pulses. Therefore, there is no need to use an encoder, and lens control is easy. The pulse motor is driven by applying a voltage (or a current) to the motor. In many cases, a sine waveform is used to drive the motor with low noise.

Next, an example of a driving method of the pulse motor will be described.

FIG. 2 is a configuration diagram of a pulse motor. Reference numerals 1 and 2 denote a motor driver circuit, reference numerals 3 and 4 denote motor windings of a two-phase pulse motor 5, reference numeral 6 denotes a magnet of the two-phase pulse motor, and reference numeral 7 denotes a microcomputer for controlling the motor. A PWM unit for outputting a pulse signal (E, F) capable of setting a duty ratio, a programmable timer unit, and a High ("
H ”) and low (“ L ”) signal output ports (A, B) and a ROM for storing data such as motor drive speed and PWM duty ratio.

FIG. 3 is an internal configuration diagram of the motor driver circuits 1 and 2. 8 and 9 are PNP transistors, 1
0 and 11 are NPN transistors, 12, 13, 14 and 15 are diodes, 16, 17, 18 and 19 are resistors, 20 and 21 are AND gates, and 22 is a NOT gate.

In FIG. 3, when the input EN1 is at "H" level and the input IN1 is at "H" level, the transistor (T
r) 8 and Tr11 are turned ON, and Tr9 and Tr11
10 is in the OFF state. Therefore, the motor winding 3 has O
A current flows from UT1 to OUT2. Input EN1
Is "H" level and the input IN1 is at "L" level,
Tr9 and Tr10 are turned on, and Tr8 and Tr10 are turned on.
11 turns off. Therefore, the motor winding 3 has O
A current flows from UT2 to OUT1. Also, input E
When N1 is at "L" level, Tr8, Tr9, Tr10 and Tr11 are at O regardless of the input level of input IN1.
The state becomes the FF state, and the outputs OUT1 and OUT2 become the high impedance state. FIG. 4 shows the relationship between input and output in these cases. The same applies to IN2, EN2, OUT3 and OUT4. In addition, the microcomputer 7 sends the PWM output E to the motor driver circuits 1 and 2.
Is input to IN1, and the PWM output F is input to IN2. As shown in FIG. 2, EN1 and EN2 may be connected to a microcomputer output port to control "H" and "L", or may be fixed at "H" level without being connected to a microcomputer. .

Next, a method of controlling the motor winding current by PWM will be described. The microcomputer 7 inputs the PWM outputs (E, F) to the motor driver circuits 1 and 2 at a constant frequency fp (see FIG. 5A). "H", "L" of this PWM
Current flows through the motor windings 3 and 4 according to the logic described above, but because the frequency fp is high, the motor windings are subjected to the duty ratio as shown in FIG. Current flows. Therefore, in order to perform sine wave driving so that vibration and noise are reduced, this P
What is necessary is just to change the WM duty ratio substantially sinusoidally. In order to drive the motor more efficiently, the change in the PWM duty ratio may be adjusted so that the amplitude of the sine wave changes according to the rotation speed.

A method of operating the duty ratio will be described below. First, the maximum value FFh and the minimum value 00 as shown in FIG.
The basic duty ratio data (Dn) as h (where h means a hexadecimal number) is stored in the ROM. The duty ratio data is, for example, a sine wave signal of one cycle
It is divided into four parts. 0 to 63 in the upper row indicate ROM addresses attached for convenience.

FIG. 7 is a graph showing a sine waveform based on FIG. 6, in which the vertical axis represents the duty ratio (Dn), and the horizontal axis A represents the ROM.
At this address, the phase position of the sine waveform of the drive current for driving the pulse motor is determined here. D is a pulse phase position, and the position of the motor can be detected by counting the pulse phase position, that is, the number of pulses, instead of the encoder. Here, a state is shown in which one cycle of the sine wave drive current is driven by eight pulses. The duty ratio data (Dn) in FIG. 6 is sequentially read out by the timer interrupt of the microcomputer 7 and is set as the PWM duty ratio. By manipulating the time of this timer interrupt, the rotation speed of the motor can be controlled. In addition,
The relationship between PWM (E) and PWM (F) is shifted by 90 degrees by shifting the read ROM address by 16.

Next, an inner focus type lens system will be described. FIG. 8 is a simple configuration diagram of an inner focus type lens system. In FIG. 8, reference numeral 101 denotes a fixed first lens group;
Denotes a second lens group (hereinafter, referred to as a zoom lens) that performs zooming, 103 denotes an aperture, 104 denotes a fixed third lens group, and 105 corrects a focus adjustment function and movement of a focal plane due to zooming. A fourth lens group having a function of a compensator lens (hereinafter, referred to as a focus lens);
Reference numeral 106 denotes an imaging surface of an imaging device such as a CCD. As is well known, in the lens system configured as shown in FIG. 8, since the focus lens 105 has both the function of the compensator lens and the focus adjustment function, even if the subject distance is equal, the focus lens 105 can focus on the imaging surface 106. The position of the focus lens 105 differs depending on the focal length.

When the focal length is changed, that is, when the zoom lens 102 is changed, the position of the focus lens 105 for focusing at an arbitrary object distance is represented by a curve as shown in FIG. The curve shown in FIG. 9 corresponds to the position where the bottom curve focuses on an infinite subject distance, and corresponds to the position where the focus is on the subject distance closer to the imaging surface as going upward. is there.
Therefore, when performing zooming while imaging an object at an arbitrary object distance, if the focus lens 105 is driven along the locus of a curve corresponding to the object distance shown in FIG. 9, zooming is performed in a focused state. Can be.

Therefore, in an imaging system having an inner focus lens, a plurality of trajectory information (cam trajectory data) shown in FIG. A control method for driving the focus lens 105 in accordance with the trajectory information for driving the lens 102 is performed.

In FIG. 9, the focus lens 1
The steepness of the movement trajectory 05 is steeper than the speed change boundary A, and in this portion, the zoom lens 102
The movement amount of the focus lens 105 is larger than the movement amount of. Therefore, when the moving speed of the zoom lens 102 is constant, the pulse motor of the focus lens must be driven at a high speed on the tele side from the speed change boundary A. In other words, the driving speed of the focus lens 105 for tracing the movement trajectory is the same as that of the zoom lens 10.
Therefore, the moving speed of the focus lens 105 can be kept low by reducing the driving speed of the zoom lens 102 on the telephoto side from the speed change boundary A because the moving speed is dependent on the moving speed of the zoom lens 102.

[0016]

However, a sine wave is input to the pulse motor, and the lens is driven through a drive transmission mechanism composed of a screw portion of the pulse motor and a rack portion of a lens frame meshing with the screw portion. In the case of driving, the frictional resistance between the screw portion of the drive transmission mechanism and the rack of the lens frame increases in a low temperature state, and the torque of the pulse motor decreases. When the pulse motor is driven at a high speed, the drive transmission mechanism comes off. Tone (such as skipping teeth) may occur. If the drive transmission mechanism loses synchronism, the lens position cannot be accurately controlled unless the lens position is reset.

A monitoring camera or the like is often installed in a place where the temperature changes drastically, or operates at night when the heating is turned off. When the temperature is low, the output torque of the pulse motor decreases, and the drive transmission mechanism is driven. May step out. In a preset function provided in a monitoring camera or the like, a zoom lens and a focus lens are driven to a position stored in advance to focus on a target object, but if the drive transmission mechanism is out of synchronization. Even if the number of movement pulses to the target lens position is counted, focusing cannot be performed because the lens position is shifted.

Although a sine wave is input to the pulse motor at the time of driving the lens, when a high-speed drive is performed at a low temperature, the torque required for driving the lens may not be obtained by the motor drive using the sine wave. . This is due to the fact that it is difficult to respond to a rapid change with a motor driven by a sine wave.

The present invention has been made in view of the above circumstances, and provides a torque required for driving the movable lens group even at a low temperature when the output torque of the lens driving means for driving the movable lens group decreases. It is an object of the present invention to provide a lens drive control device and method capable of outputting and an optical apparatus using the same.

[0020]

According to the present invention, there is provided a lens drive control apparatus comprising: (1) a movable lens group movable in an optical axis direction;
Lens driving means for driving the moving lens group at a predetermined speed, temperature detecting means for detecting an environmental temperature, and drive control means for driving and controlling the lens driving means based on temperature data obtained from the temperature detecting means. Wherein the drive control means changes a driving condition of the movable lens group by the lens drive means based on temperature data obtained from the temperature detection means.

Further, the lens drive control device according to the present invention comprises (1)
-2) at least one or more moving lens groups movable in the optical axis direction, lens driving means for driving the moving lens groups at at least two speeds, temperature detecting means for detecting environmental temperature, Drive control means for driving and controlling the lens drive means based on temperature data obtained from the temperature detection means, wherein the drive control means makes the temperature data obtained from the temperature detection means higher than a preset temperature. When it is determined that the temperature is low, the driving condition of the moving lens group by the lens driving unit is changed.

In particular, (1-3) above (1) or (1-
In the lens drive control device of 2), a stepping motor is used as the lens drive means;
4) In the lens drive control device according to any one of the above (1) to (1-3), the drive control means drives the movable lens group as a change in the drive condition of the movable lens group by the lens drive means. Lowering the maximum speed to
-5) In the lens drive control device according to any one of the above (1) to (1-3), the drive control means controls the moving lens group by changing the driving condition of the moving lens group by the lens driving means. (1-6) In the lens drive control device according to any one of (1) to (1-3), the drive waveform for driving the lens drive unit is changed from a sine wave to a rectangular wave. The detecting means is characterized by detecting the ambient temperature of the lens driving means.

The optical apparatus according to the present invention is characterized in that (2) any one of the lens drive controllers (1) to (1-6) is used.

The lens drive control method according to the present invention is: (3) a lens drive control method for controlling a lens drive means for driving a moving lens group at a predetermined speed in an optical axis direction. It is characterized by including a detecting step and a drive controlling step of changing a driving condition of the moving lens group by the lens driving means based on the temperature data obtained in the temperature detecting step.

The lens drive control method according to the present invention comprises:
-1) a lens driving control method for driving and controlling a lens driving unit that drives at least one or more moving lens groups in an optical axis direction at at least a second speed, a temperature detecting step of detecting an environmental temperature; A judging step of judging whether the temperature data obtained in the temperature detecting step is lower than predetermined temperature data, and driving the moving lens group by the lens driving means when it is judged in the judging step that the temperature is low. And a drive control step of changing conditions.

In particular, (3-2) the above (3) or (3-
In the lens drive control method of 1), a stepping motor is used as the lens drive means;
3) In the lens driving control method according to any one of the above (3) to (3-2), the driving control step of changing the driving condition of the moving lens group by the lens driving unit includes driving the moving lens group. Lowering the maximum speed of
(3-4) In the lens driving control method according to any one of the above (3) to (3-2), the moving lens group is changed to a driving control step for changing a driving condition of the moving lens group by the lens driving unit. Changing the driving waveform to the lens driving means for driving from a sine wave to a rectangular wave; (3
-5) In the lens drive control method according to any one of the above (3) to (3-2), the temperature detecting step is characterized by detecting an ambient temperature of the lens driving means.

Further, the optical apparatus of the present invention is characterized in that (4) any one of the lens drive control methods (3) to (3-5) is used.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a schematic configuration diagram of a lens system according to a first embodiment used for an imaging device such as a television camera. FIG. 1 is not limited to this embodiment, but relates to all embodiments of the present invention.

In FIG. 1, 101, 102, 103,
Reference numerals 104 and 105 denote elements constituting an inner focus type lens system. Reference numeral 101 denotes a fixed front lens group, and reference numeral 102 denotes a second lens group (hereinafter, referred to as a zoom lens) as a movable lens group for performing zooming. Name),
103 is an aperture, 104 is a fixed third lens group, 105
Reference numeral denotes a fourth lens group (hereinafter, referred to as a focus lens) as a moving lens group having both a competition function and a focusing function.

Zoom lens 102 and focus lens 1
Numerals 05 are each held by a lens frame (not shown), and are guided by a guide shaft (not shown) so as to be movable along the optical axis direction. A rack provided on the lens frame and a threaded portion of an output shaft (not shown) of lens driving motors 118 and 120 to be described later are meshed without any play by urging means. Rotates forward and backward, the zoom lens 102 and the focus lens 105 move forward and backward along the optical axis. That is, the rack portion of the lens frame of the zoom lens 102 and the focus lens 105 and the motor 1
A drive transmission mechanism is constituted by the screw portions 18 and 120, and the rack portion of the lens frame converts the rotary motion of the screw portions of the motors 118 and 120 into a linear motion for moving the zoom lens 102 and the focus lens 105 in the optical axis direction, respectively. Convert.

Reference numerals 123 and 125 denote zoom lenses 1 respectively.
02 and a switch for detecting that the focus lens 105 is at the reference position. 124 and 126 are photo sensors. The switches 123 and 125 and the photo sensors 124 and 126
Are incorporated in the focus lens 105.

Here, description will be made using an inner focus type lens system, but the present invention is not limited to this, and a front focus lens which drives a front lens located forward of the zoom lens to perform focus adjustment is used. A system may be used.

The image light transmitted through this lens system is C
An image is formed on the surface of the image sensor 106 such as a CD, and is converted into a video signal by photoelectric conversion. Reference numeral 107 denotes an amplifier or an impedance converter, and reference numeral 108 denotes a camera signal processing circuit. The processed video signal is amplified to a specified level by an amplifier 109, processed by an LCD display circuit 110, and then displayed on a display device 131 such as an LCD. To display the shot image. On the other hand, the video signal amplified by the amplifier or the impedance converter 107 is sent to the aperture control circuit 112 and the AF evaluation value processing circuit 111. The aperture control circuit 112 controls the IG driver 11 in accordance with the video signal input level.
3. Drive the IG meter 114 to control the aperture 103 and adjust the light amount. The AF evaluation value processing circuit 111 extracts and processes only the high-frequency components of the video signal in the ranging frame according to the gate signal from the ranging frame generating circuit 116.

Reference numeral 115 denotes an AF microcomputer (referred to as an AF microcomputer) which constitutes drive control means together with a system control microcomputer (hereinafter referred to as a system controller) 121, which will be described later. Control and ranging frame control for changing the ranging area are performed. The AF microcomputer 115 communicates with a system control microcomputer (hereinafter, referred to as a system controller) 121.
Switch 122 reads by A / D conversion or the like
(A voltage corresponding to the rotation angle of the operation member is output by the unitized zoom SW. The variable speed zoom is performed according to the output voltage) and information stored in the ROM in the AF microcomputer 115. Based on the cam trajectory data shown in FIG. 9, zooming operation information such as a zoom direction and a focal length during zooming controlled by the AF microcomputer 115 are exchanged with each other.

Reference numerals 117 and 119 denote the AF microcomputer 1
A current waveform changeable driver for outputting driving energy to a lens driving motor in accordance with a driving command of the zoom lens 102 and the focus lens 105 output from the zoom lens 102 and the zoom lens 102
And a motor as lens driving means for driving the focus lens 105.

Reference numeral 130 denotes a temperature detector as temperature detecting means, which sends detected temperature information (temperature data) to the AF microcomputer 115. When the AF microcomputer 115 determines that the temperature is low based on the temperature information obtained from the temperature detector 130, the AF microcomputer 115 sets the maximum speed in driving the lens to a value lower than that at normal temperature.

Here, the motors 118 and 1 for driving the lenses are used.
Assuming that 20 is a stepping motor, a method of driving the motor will be described below. These stepping motors 1
Reference numerals 18 and 120 are configured using the operation principle of the pulse motor shown in FIGS. The AF microcomputer 115 executes the zoom motor 118 and the focus motor 120 by performing program processing of information from the zoom switch 122 and zooming operation information such as a zoom direction and a focal length during zooming.
The driving speed of the zoom motor 118 is determined as the rotation frequency signal of each stepping motor.
17 and driver 11 for driving focus motor 120
Send to 9. The drive / stop commands for the motors 118 and 120 and the rotation direction commands for the motors 118 and 120 are sent to the drivers 117 and 119. The drive / stop signal and the rotation direction signal are mainly determined according to the state of the zoom switch 122 for the zoom motor 118, and the drive command for the focus motor 120 is determined by processing in the AF microcomputer 115 during AF and zoom. According to. Driver 11 for driving motors 117 and 118
7 and 119 set the phases of the four motor excitation phases to forward rotation and reverse rotation according to the rotation direction signal, and apply the applied voltages of the four motor excitation phases according to the received rotation frequency signal. (Or current) while changing the output, turning on the output to the motor in response to the drive / stop command while controlling the rotation direction and rotation frequency of the motor
/ OFF.

FIG. 10 is a flowchart showing a control method of the zoom motor of the zoom lens which is processed by using the above lens system.

In FIG. 10, at step S1001, the AF microcomputer 115 first receives the information of the zoom switch 122 read by the system controller 121, and if a zoom drive command has been issued, the flow proceeds to step S1002.

Next, in step S1002, the temperature detector 130 detects the temperature around the motors 118 and 120, and sends the information (temperature data) to the AF microcomputer 115.

In step S1003, the AF microcomputer 1
15 determines whether or not the temperature is low based on the information obtained from the temperature detector 130. If it is determined that the temperature is low, the process proceeds to step S1004. If it is determined that the temperature is not low, the process proceeds to step S1005.

In step S1004, it is determined whether the zoom drive command read in step S1001 is a high-speed drive command. If it is a high-speed driving command, the process proceeds to step S1006, and if it is not a high-speed driving command, the process proceeds to step S1005.

In step S1005, the AF microcomputer 1
15 is the zoom switch 1 received in step S1001
PWM is input to the zoom motor driving driver 117 in accordance with the driving speed based on the information of the zoom motor 22 and the zoom motor 1
18 is driven.

In step S1006, a middle speed level is set as the maximum speed at which the motor can be driven from the speed level table previously set and stored in the memory of the AF microcomputer 115.

Next, in step S1007, as in step S1005, the AF microcomputer 115
The PWM is input to the zoom motor driving driver 117 according to the driving speed based on the information of the zoom switch 122 received at 01, and the zoom motor 118 is driven. In this case, the maximum speed set in step S1006 is set as a limit.

Here, the method of determining the low temperature state in step S1003 will be described. Zoom motor 1 in advance
It is assumed that the relationship between the drive characteristics of the motor 18 and the output torque of the motor with respect to speed and temperature is known, and that the torque required for driving the lens is also known.
Then, based on the information, the motor speed data capable of producing a torque required for driving the lens at a low temperature is associated with a predetermined set temperature in advance by the AF microcomputer 115.
Stored in the ROM. In step S1003, in the temperature state obtained from the temperature detector 130, when the temperature information from the temperature detector 130 is lower than a predetermined set temperature, that is, when the zoom motor 118 is operated at the maximum speed set at normal temperature. When it is determined that the torque required for driving the lens cannot be obtained during driving, it is determined that the temperature is low.

Step S1005 is a conventional motor driving operation, in which a sine wave current as shown in FIG. 5 is supplied to the motor winding based on the duty ratio data shown in FIG. 6 to drive the motor.

As described above, in this embodiment, when the AF microcomputer 115 determines that the temperature is low based on the temperature information obtained from the temperature detector 130, the zoom lens 102
The driving condition of the zoom lens 102 by the zoom motor 118 is changed by setting, for example, a middle speed level as the maximum speed of the zoom motor 118 from a speed level table in which the driving speed of the zoom lens 118 is variable. Accordingly, the zoom microcomputer 118 is driven and controlled by the AF microcomputer 115 with the changed speed level as the maximum speed.
The sliding resistance between the screw portion of the drive transmission mechanism and the rack portion of the lens frame in a low temperature state can be reduced, so that a situation in which the drive transmission mechanism loses synchronism (such as tooth skipping) can be avoided. Even at a low temperature when the output torque decreases, the torque required for driving the zoom lens 102 can be output.

(Second Embodiment) This embodiment is an example of a motor control method for changing a drive waveform of a zoom motor based on temperature information. FIG. 11 is a flowchart illustrating a motor control method according to the present embodiment. In addition,
Also in this embodiment, the processing is executed by using the lens system shown in FIG.

Referring to FIG. 11, in step S1101, the AF microcomputer 115 receives the information of the zoom switch 122 read by the system controller 121, and if a zoom drive command has been issued, the flow proceeds to step S1102.

Next, in step S1102, the temperature detector 130 detects the temperature around the motors 118 and 120 and sends the information (temperature data) to the AF microcomputer 115.

In step S1103, the AF microcomputer 1
15 determines whether or not the temperature is low based on the information obtained from the temperature detector 130. If it is determined that the temperature is low, the process proceeds to step S1104. If it is determined that the temperature is not low, the process proceeds to step S1105.

In step S1104, it is determined whether the information of the zoom switch 122 read out in step S1101 is a high-speed driving command. If it is a high-speed driving command, the process proceeds to step S1106. If it is not a high-speed driving command, the process proceeds to step S1105.

In step S1105, the AF microcomputer 1
15 is the zoom switch 1 received in step S1101
PWM is input to the zoom motor driving driver 117 in accordance with the driving speed based on the information of the zoom motor 22 and the zoom motor 1
18 is driven.

In step S1106, the AF microcomputer 1
15 switches the PWM output waveform from a sine waveform to a rectangular waveform, inputs PWM to the zoom motor driving driver 117 according to the driving speed based on the information of the zoom switch 122 received in step S1101, and drives the zoom motor 118. I do.

The method for determining the low temperature state in step S1103 is the same as that in step S1003 in the first embodiment, and a detailed description thereof will be omitted.

Here, the processing in step S1106 will be described. In the normal motor driving, that is, in step S1105, a sine wave current as shown in FIG. 5 is supplied to the motor winding based on the duty ratio data shown in FIG. 6 to drive the zoom motor 118. On the other hand, when high-speed driving is performed at a low temperature, a torque required for driving a lens may not be obtained by a conventional motor driving using a sine wave. Therefore, the output waveform for driving the motor is made a rectangular wave. To output a rectangular wave, the duty ratio may be set to FFh or 00h. To change the driving speed, the reading speed may be changed by a timer interrupt as in the case of the conventional motor.

As described above, in this embodiment, when the AF microcomputer 115 determines that the temperature is low based on the temperature information obtained from the temperature detector 130, the zoom motor 118
The driving condition of the zoom lens 102 by the zoom motor 118 is changed by changing the driving waveform to the square wave from the sine wave. As a result, the zoom motor 118
Since the microcomputer 115 controls the drive with the rectangular wave, the microcomputer 115 can sufficiently respond to a rapid change such as high-speed drive, and can drive the zoom lens 102 even at low temperatures when the output torque of the zoom motor 118 decreases. The required torque can be output.

(Third Embodiment) In the first embodiment described above, the method of lowering the maximum speed at the time of low temperature in the motor control of the zoom lens has been described. The same can be applied to driving.

FIG. 12 is a flowchart showing a control method of the focus lens motor in this embodiment. Note that, also in the present embodiment, the processing is performed using the lens system shown in FIG.

In FIG. 12, in step S1201, the AF microcomputer 115 proceeds to step S1202 if a focus drive command has been issued.

Next, in step S1202, the temperature detector 130 detects the temperature around the motors 118 and 120 and sends the information (temperature data) to the AF microcomputer 115.

In step S1203, the AF microcomputer 1
15 determines whether or not the temperature is low based on the information obtained from the temperature detector 130. If it is determined that the temperature is low, the process proceeds to step S1204. If it is determined that the temperature is not low, the process proceeds to step S1205.

In step S1204, it is determined whether the focus drive command read in step S1201 is a high-speed drive command. If it is a high-speed driving command, the process proceeds to step S1206. If not, the process proceeds to step S1205.

In step S1205, the AF microcomputer 1
15 drives the focus motor 120 by inputting PWM to the focus motor drive driver 119 according to the drive speed based on the focus lens drive command in step S1201.

In step S1206, a middle speed level is set as the maximum speed at which the motor can be driven from a speed level table previously set and stored in the memory of the AF microcomputer 115.

Next, in step S1207, similarly to step S1205, the AF microcomputer 115 inputs PWM to the focus motor driving driver 119 in accordance with the driving speed based on the focus lens driving command in step S1201, and drives the focus motor 120. I do. In this case, the maximum speed set in step S1206 is set as a limit.

Here, the processing in step S1201 will be described. First, the AF microcomputer 115 receives from the system controller 121 whether the focus mode state is the AF (autofocus) mode or the MF (manual focus) mode. In AF mode,
It is determined based on the value of the high-frequency component of the video signal output from the AF evaluation value processing circuit 111 whether or not the camera is in focus. If it is not in the in-focus state, it is necessary to drive the focus lens 105 so that it is in focus.
Proceed to. In the case of the MF mode, it is determined whether or not a command indicating manual focus lens driving has been issued. If a driving command has been issued, the process proceeds to step S1202.

As described above, in this embodiment, when the AF microcomputer 115 determines that the temperature is low based on the temperature information obtained from the temperature detector 130, the focus lens 1
For example, from the speed level table in which the drive speed of the drive lens 05 is variable, the middle speed level is set to the focus lens 105.
By setting the maximum speed of the focus motor 1
The driving condition of the focus lens 105 is changed. As a result, the focus motor 120 is driven and controlled by the AF microcomputer 115 with the changed speed level being the highest speed, so that the sliding friction between the screw portion of the drive transmission mechanism and the rack portion of the lens barrel in a low temperature state can be reduced, It is possible to avoid a situation in which the drive transmission mechanism loses synchronism (such as tooth skipping), and therefore, it is possible to output a torque necessary for driving the focus lens 105 even at a low temperature when the output torque of the focus motor 120 decreases. it can.

(Fourth Embodiment) In the second embodiment described above, a method of driving the zoom motor with a rectangular drive waveform at a low temperature in the motor control of the zoom lens has been described. The same applies to the drive of the focus lens 105 as well as the drive of the focus lens 105.

FIG. 13 is a flowchart showing a control method of the focus lens motor in this embodiment.
Note that, also in the present embodiment, the processing is performed using the lens system shown in FIG.

In FIG. 13, in step S1301, the AF microcomputer 115 first proceeds to step S1302 if a focus drive command has been issued.

Next, in step S1302, the temperature detector 130 detects the temperature around the motors 118 and 120, and sends the information (temperature data) to the AF microcomputer 115.

In step S1303, the AF microcomputer 1
15 determines whether or not the temperature is low based on the information obtained from the temperature detector 130. If it is determined that the temperature is low, the process proceeds to step S1304. If it is determined that the temperature is not low, the process proceeds to step S1305.

In step S1304, it is determined whether the information of the focus drive command read in step S1301 is a high-speed drive command. If it is a high-speed driving command, the process proceeds to step S1306; if not, the process proceeds to step S1305.

In step S1305, the AF microcomputer 1
15 drives the focus motor 120 by inputting PWM to the focus motor drive driver 119 according to the drive speed based on the focus lens drive command in step S1301.

In step S1306, the AF microcomputer 1
Reference numeral 15 switches the PWM output waveform from a sine waveform to a rectangular waveform, inputs the PWM to the focus motor driving driver 119 according to the driving speed based on the focus lens driving command in step S1301, and drives the focus motor 120. Step S1306
Is the same as that in step S1106 of the second embodiment described above, and a detailed description thereof will be omitted.

As described above, in this embodiment, when the AF microcomputer 115 determines that the temperature is low based on the temperature information obtained from the temperature detector 130, the focus motor 1
20 is changed from a sine wave to a rectangular wave, so that the focus lens 1
05 is changed. As a result, since the focus motor 120 is driven and controlled by the AF microcomputer 115 using a rectangular wave, the focus motor 120 can sufficiently respond to rapid changes such as high-speed driving, and the focus lens 105 can be driven even at a low temperature when the output torque of the focus motor 120 decreases. It is possible to output torque required for lens driving, particularly for high-speed driving.

In each of the above embodiments, the temperature detector 130 detects the temperature around the motors 118 and 120. However, the temperature detector 130 may detect the environmental temperature of the photographing apparatus.

[0080]

As described above, according to the lens drive control apparatus of the present invention, a moving lens group movable in the optical axis direction, a lens driving means for driving the moving lens group at a predetermined speed, Temperature detection means for detecting an environmental temperature; and drive control means for driving and controlling the lens driving means based on temperature data obtained from the temperature detection means, wherein the drive control means is provided with a temperature obtained from the temperature detection means. Since the driving condition of the moving lens group by the lens driving unit is changed based on the data, it is possible to output the torque necessary for driving the moving lens group even at a low temperature when the output torque of the lens driving unit decreases. In addition, the drive transmission mechanism can be prevented from stepping out, and the torque required for high-speed driving of the movable lens group can be obtained.

Further, according to the lens drive control method of the present invention, there is provided a lens drive control method for controlling a lens drive means for driving a moving lens group at a predetermined speed in the optical axis direction. A temperature detecting step; and a drive controlling step of changing a driving condition of the moving lens group by the lens driving means based on the temperature data obtained in the temperature detecting step, so that the output torque of the lens driving means decreases. Even at the time, the torque required for driving the moving lens group can be output, and the drive transmission mechanism can be prevented from stepping out, and the torque required for high-speed driving of the moving lens group can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a lens drive control device according to the present invention.

FIG. 2 is a block diagram of a pulse motor.

FIG. 3 is an internal configuration diagram of a motor driver circuit.

FIG. 4 is a diagram showing an input / output relationship of a motor driver circuit.

FIG. 5 is a diagram showing a relationship between a PWM duty ratio and a current;

FIG. 6 is a diagram showing duty ratio data.

FIG. 7 is a diagram showing a sine waveform of the duty ratio data of FIG. 6;

FIG. 8 is a configuration diagram of an inner focus type lens system.

FIG. 9 is a conceptual diagram of cam locus data.

FIG. 10 is a flowchart illustrating processing according to the first embodiment;

FIG. 11 is a flowchart illustrating a process according to the second embodiment;

FIG. 12 is a flowchart illustrating a process according to the third embodiment;

FIG. 13 is a flowchart illustrating a process according to the fourth embodiment;

[Explanation of symbols]

Reference Signs List 102 zoom lens (moving lens group) 105 focus lens (moving lens group) 118 zoom lens motor (lens driving unit) 120 focus lens motor (lens driving unit) 115 AF microcomputer (drive control unit) 121 microcomputer for system control ( Drive control means) 130 Temperature detector (Temperature detection means)

Claims (14)

[Claims] A movable lens group movable in an optical axis direction;
Lens driving means for driving the moving lens group at a predetermined speed, temperature detecting means for detecting an environmental temperature, and drive control means for driving and controlling the lens driving means based on temperature data obtained from the temperature detecting means. Wherein the drive control means changes a drive condition of the moving lens group by the lens drive means based on temperature data obtained from the temperature detection means. 2. At least one or more moving lens groups movable in the optical axis direction, lens driving means for driving the moving lens groups at at least two speeds, and temperature detecting means for detecting an environmental temperature. Drive control means for driving and controlling the lens driving means based on the temperature data obtained from the temperature detection means, wherein the drive control means comprises a preset temperature at which the temperature data obtained from the temperature detection means is set in advance. A lens drive control unit that changes a driving condition of the moving lens group by the lens driving unit when it is determined that the temperature is lower than the temperature. 3. The lens drive control device according to claim 1, wherein a stepping motor is used as the lens drive means. 4. The lens drive control device according to claim 1, wherein the drive control unit is configured to change a driving condition of the movable lens group by the lens drive unit. A lens drive control device characterized by lowering the maximum speed for driving the lens. 5. The lens driving control device according to claim 1, wherein the driving control unit is configured to change a driving condition of the moving lens group by the lens driving unit. A driving waveform for driving the lens driving means to the lens driving means is changed from a sine wave to a rectangular wave. 6. The lens driving control device according to claim 1, wherein said temperature detecting means detects an ambient temperature of said lens driving means. apparatus. 7. An optical apparatus using the lens drive control device according to claim 1. Description: 8. A lens driving control method for driving a lens driving means for driving a moving lens group at a predetermined speed in an optical axis direction, comprising: a temperature detecting step for detecting an environmental temperature; A driving control step of changing a driving condition of the moving lens group by the lens driving unit based on the obtained temperature data. 9. A lens driving control method for driving at least one or more moving lens groups at a speed of at least two speeds in an optical axis direction, wherein the temperature detecting step detects an environmental temperature. A determining step of determining whether the temperature data obtained in the temperature detecting step is lower than predetermined temperature data; and determining whether or not the moving lens group by the lens driving means when the determining step determines that the temperature is low. And a drive control step of changing the drive conditions of the above. 10. A lens drive control method according to claim 8, wherein a stepping motor is used as said lens drive means. 11. The lens drive control method according to claim 8, wherein the drive control step of changing a drive condition of the movable lens group by the lens drive means drives the movable lens group. A lens drive control method characterized by lowering the maximum speed for performing lens driving. 12. The lens drive control method according to claim 8, wherein the drive control step of changing a drive condition of the movable lens group by the lens drive means drives the movable lens group. A driving waveform to the lens driving means for changing the driving waveform from a sine wave to a rectangular wave. 13. The lens driving control method according to claim 8, wherein the temperature detecting step detects an ambient temperature of the lens driving means as the temperature detecting step. Method. 14. An optical apparatus using the lens drive control method according to claim 8. Description: