JPH09304680A - Zoom lens controller for television camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens for a television camera capable of stably controlling a servo system in accordance with the upper limit of a current which can be supplied from the camera side by recognizing the limit of the current which is different by every camera. SOLUTION: The limit value of the current of every camera is set by a selection switch 70 so as to discriminate whether or not the current supplied from the connected camera is the current high enough to independently perform zooming operation, focusing operation and the operation of an extender. In the case the limit value is smaller than a specified current value, a signal for controlling a zoom control circuit 22 and a focus control circuit 42 is outputted from a central processing unit 30 so that zooming and focusing operation may be inhibited in the midst of the operation of the extender. Thus, the operation is stably performed within the limit value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens control device for a television camera, and more particularly to a television camera configured to operate zoom, focus, extender, etc. by a current supplied from a connected camera. The present invention relates to current control technology for zoom lenses.

[0002]

2. Description of the Related Art As a zoom lens used in a television camera for broadcasting, it is known that all operations of zoom, focus, iris, extender and the like are controlled by a servo system. In this type of all-servo-operated zoom lens (or full-servo-operated zoom lens), the power of the servo system is supplied from the television camera side.

On the other hand, a television camera has an upper limit on the current that can be supplied to the zoom lens side, for example, 70.
Some can supply up to 0 mA, and some can supply up to 2 A.

[0004]

However, in some cases, a current larger than the current that can be supplied from the camera side is required, and the conventional zoom lens must be provided with an auxiliary battery to make up for the shortage. Further, if the servo operation is performed in excess of the upper limit of the current supply from the camera side, such as simultaneously driving a plurality of servo systems, the voltage will not be stable and the control signal will fluctuate. In particular, in a focus system that requires high lens position accuracy, there is a problem that defocusing occurs if the control signal is not stable.

The present invention has been made in view of such circumstances, and a television capable of stably controlling the servo system according to the upper limit of the current that can be supplied from the camera side without providing an auxiliary battery. An object is to provide a camera lens.

[0006]

In order to achieve the above object, the present invention receives power supply from a connected camera side,
In a control device for controlling a zoom lens for a television camera having a plurality of current consuming means that consumes a current by performing an operation according to an operation command from a corresponding external operating means, a limit indicating an upper limit of a current that can be supplied from the camera side It is characterized by including limit value setting means for setting a value.

According to the present invention, the limit value of the current that can be supplied which is different for each camera is set by the limit value setting means, so that it is sufficient to operate all the current consumption means independently from the connected camera. Determine if current can be supplied. Then, when the set limit value is larger than the predetermined current value, each current consuming means can be independently operated without limitation. On the other hand,
If the set limit value is smaller than the specified current value, stable operation of each current consuming device within the range of the limit value is prevented by not operating a specific combination of multiple current consuming devices at the same time. Can be done.

For example, a mode in which the operation of the zoom and focus driving means is prohibited during the operation of the extender driving means can be considered. Normally, while driving the extender, a good image cannot be obtained even if the zoom or focus is operated, so there is no advantage in operating these simultaneously. As described above, it is desirable to impose a limitation on the operation of the combination of the current consuming means corresponding to the operation that does not make sense to operate them simultaneously during shooting.

On the other hand, it is desirable to enable as many operations as possible for those that need to be operated at the same time. Therefore, the current supplied to at least one current consuming means among a plurality of current consuming means associated with the operation is desired. By limiting the upper limit and controlling the total current consumption value of the current consumption means to be equal to or less than the limit value, the limited current can be distributed to various operations.

According to another aspect of the present invention, the current consumed by the current consuming means to be operated is detected by the detecting means, and when the current value exceeds a predetermined threshold, The voltage varying means is controlled to reduce the voltage applied to the current consuming means to reduce the current consumption. This allows
The limited current supplied from the camera side can be distributed to many current consumption means.

[Detailed Description of the Invention]

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a zoom lens control device for a television camera according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing an example of a usage mode of a full servo operation type zoom lens to which a zoom lens control device for a television camera according to the present invention is applied. In the same figure, a state in which a full-servo operation type zoom lens 10 is connected to a television camera 4 supported by a platform 2 and a cameraman operates the zoom lens 10 is shown.

The platform 2 is provided with two operation rods 2A, 2B, and the operation rod 2A on the right hand side of the cameraman.
A focus demand 12 for operating the focus is attached to the camera, and a zoom rate demand 1 for operating the zoom speed is attached to the operation rod 2B on the left hand side of the cameraman.
4 is attached. Focus Demand 12 is
A position control signal for instructing the moving position of the focus lens group is output according to the rotation operation amount of the ring (focus ring). Then, the movable focus lens group in the lens barrel is driven based on this position control signal.

Further, the zoom rate demand 14 outputs a speed control signal for zooming to the wide-angle side or the telephoto side according to the rotating direction and the rotating amount of the zoom ring. Based on the speed control signal, the variable power lens group in the lens barrel is speed-controlled and driven. The cameraman operates the focus demand 12 with the right hand while watching the captured image on the viewfinder 16 to move the movable focus lens group in the lens barrel to adjust the focus, and with the left hand the zoom ring of the zoom rate demand 14. By operating the zoom lens group (first and second zoom lens groups)
It is possible to perform zooming adjustment by moving while being defined by a predetermined optical positional relationship.

Although not shown in detail in FIG. 1, a drum holding an extender lens is rotatably assembled to the zoom lens for a television camera. This extender drum is rotationally driven by a motor (extender motor) that operates in response to the operation of an extender switching knob provided on the side of the mount frame, so that the extender drum enters or retracts from the optical axis. ing.

Further, an iris mechanism (not shown) is provided on the lens barrel so that the aperture value can be changed by the driving force of the iris motor. The operations such as the zoom, focus, extender, and iris are all controlled by the servo system, and the electric power for driving these servo systems is supplied from the connected TV camera 4 side. Note that there is a pattern projector (PJ) lamp or the like that operates by the electric power supplied from the television camera 4 side.

An upper limit is set for the current that can be supplied from the camera side to the lens side, and the upper limit value (limit value) varies depending on the camera model. FIG. 2 is a block diagram showing a main configuration of a zoom lens control device for a television camera to which the present invention is applied. The zoom lens controller is
It mainly comprises a servo system corresponding to each operation such as zoom, focus, and extender, a means for recognizing the current limit of the camera, and a means for controlling each servo system according to the recognized current limit. .

The zoom signal generating means 20 corresponds to the zoom rate demand 14 shown in FIG. 1, and when the zoom ring is rotated, it generates an electric signal according to the rotating direction and the amount of rotation. This electric signal is a speed command signal that commands a zoom speed, and is applied to the zoom control circuit 22 as a zoom signal. The zoom control circuit 22 outputs a servo signal according to the input zoom signal and drives the zoom motor 24. The rotational force of the zoom motor 24 is changed by a power transmission means (not shown) in the zoom lens group 26 in the lens barrel.
And the zoom lens group 26 moves back and forth along the optical axis. The position (zoom position) of the variable power lens group 26 is detected by the potentiometer 28, and the position detection signal is notified to the zoom control circuit 22.

The focus signal generating means 40 corresponds to the focus demand 12 shown in FIG. 1, and when the operation ring of the focus demand 12 is rotated, it generates an electric signal according to the rotation amount. This electric signal is a position movement command signal that commands the focus position, and is input to the focus control circuit 42 as a focus signal. The focus control circuit 42 outputs a servo signal according to the input focus signal to drive the focus motor 44. The rotational force of the focusing motor 44 is transmitted to the movable focus lens group 46 in the lens barrel by a power transmission unit (not shown), and the movable focus lens group 46 moves back and forth along the optical axis.

The position of the movable focus lens group 46 is detected by the potentiometer 48, and the position detection signal is notified to the focus control circuit 42. The focus control circuit 42 stops driving the focusing motor 44 when the position indicated by the position detection signal matches the position instructed by the focus signal generating means 40. This enables focus position control with high followability.

The extender signal generating means 50 corresponds to the above-mentioned extender switching knob, and when the extender switching knob is operated, the operation signal is converted into a digital signal by the A / D converter 52 to be processed by the central processing unit (CPU). ) 30. The CPU 30 outputs an extender signal based on the input operation signal.
This extender signal is converted into an analog signal by the D / A converter 54, and the extender control circuit 55
Is added to

The extender control circuit 55 outputs a servo signal according to the input extender signal to drive the extender driving motor 56. The rotational force of the extender driving motor 56 is transmitted to the drum 60 that holds the extender lens, and the extender enters or retracts within the optical axis. The rotation position of the drum 60 is detected by the sensor 62, and the detection signal is A
C after being converted to a digital signal by the / D converter 64
The PU 30 is notified.

Camera current limit select switch 70
Is configured so that the current limit can be set stepwise according to the camera used. For example, when a camera that can supply a current of 500 mA or more and less than 700 mA is connected, the limit a is selected.
Limit b when connecting a camera of less than 1A, limit c when connecting a camera of 1A or more and less than 1.5A,
The limit d is selected when a camera of 1.5 A or more and less than 2 A is connected, and the limit e is selected when a camera of 2 A or more is connected. A signal indicating the selected limit is notified to the CPU 30, and the CPU 30 recognizes the current limit of the camera.

Such a stepwise select switch 70
Instead of, the limit value set for each camera may be numerically input. Alternatively, the camera side may be provided with an identifying means for indicating a current limit value, and the lens side may be configured to recognize the camera current limit through the identifying means by connecting with the lens. The CPU 30
The operation of the zoom control circuit 22 and the focus control circuit 42 is prohibited based on the current limit value input by the select switch 70 and the extender drive signal output from the extender signal generating means 50.

FIG. 3 is a flow chart showing the flow of processing of the zoom lens control device for the television camera shown in FIG.
The CPU 30 first recognizes the current limit value input by the select switch 70 (step S301, only step numbers are shown below), and the current limit is 2A.
It is determined whether or not this is the case (S302). The reference value of 2A is defined from the viewpoint of a current value that is sufficient to effectively perform all the operations on the lens side, and if the current limit is 2A or more, all the operations on the lens side operate independently. Sufficient current may be provided to allow it. Therefore,
When the recognized current limit value is 2 A or more, all operations such as zooming, focusing, and extender are set to an independently operable state and a full servo state (S303).

On the other hand, if it is determined in S302 that the current limit value is less than 2 A, the current will be insufficient if all operations on the lens side are operated independently, so that the zoom and focus are controlled during the operation of the extender. Limit movement. That is, it is determined whether or not the extender control signal indicating whether the extender has been operated is input (S304), and the extender control signal input (EXT.CO) indicating that the extender has been operated is input.
NT.IN), the CPU 30 causes the zoom control circuit 22
A control signal for prohibiting the operation is output to the focus control circuit 42 (S305). As a result, the zoom and focus operations are stopped. After that, the process is S3.
Returning to 04, the zoom and focus operations are prohibited while the extender is being operated.

In S304, when there is no signal input (EXT.CONT.IN) of the extender control signal indicating that the extender has been operated, the CPU 30 allows the zoom control circuit 22 and the focus control circuit 42 to operate. A control signal is output (S306). Therefore, when the zoom rate demand 14 or the focus demand 12 is operated, the zoom or focus operation is performed according to the operation. Then, the process returns to S304, and the zoom and focus operations can be performed while the extender is not operated.

As described above, the operation of the zoom or focus is prohibited or permitted depending on whether or not the extender is operated. A good image can be obtained even if the zoom or focus is operated while the extender is driven. Because there is no
This is because there is no advantage in operating these simultaneously.
As described above, it is desirable to impose restrictions on the operations of combinations of operations that do not make sense to operate simultaneously during shooting.

According to the zoom lens control device for a television camera configured as described above, it is possible to perform a stable operation for operations such as zoom, focus, and extender within the range of the limit value specified for each camera. it can. FIG. 4 is a block diagram showing the configuration of another embodiment of the zoom lens control device for a television camera to which the present invention is applied. The same or similar components as those of the television camera zoom lens controller shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

When the zoom signal is input from the zoom signal generating means 20, the zoom control circuit 22 notifies the CPU 30 of a signal (ZOOM CONT.IN) meaning input of the zoom signal. In addition, the focus control circuit 4
When a focus signal is input from the focus signal generating means 40, the reference numeral 2 notifies the CPU 30 of a signal (FOCUS CONT.IN) meaning input of the focus signal.

A storage device 74 is connected to the CPU 30.
Current limit table stored in the storage device 74
You can read the required data from the data
Swelling. In the storage device 74, as shown in FIG.
The current limit table is stored as data.
In the figure, a to e are selected stepwise by the select switch 70.
I shows the selection limit_Ki(I = 1,2 ...) is a turtle
Current limit value, I _Zi(I = 1, 2, ...) is the zoom current
Limit value, I_Fi(I = 1, 2, ...) is the focus current
Indicates the mitt value.

For cameras whose camera current limit value specified for each camera is greater than or equal to I _{K1 and} less than I _K2 , the limit a,
Limit b is selected when I _K2 or more and less than I _K3, limit c is selected if I _K3 or more and less than I _K4 , limit d is selected if I _K4 or more and less than I _K5 , and limit e is selected if I _K5 or more and less than I _K6. It will be a response that. As described in FIG. 2, for example, I _K2 is 500 mA, I _K3 is 700 mA, and I _K4 is 1.
A and I _K5 are 1.5A and I _K6 is 2A.

For each step of the selection limits a to e,
A zoom current limit I _Z and a focus current limit I _F according to the operation status of the zoom focus are defined. That is, when only the zoom signal indicating that the zoom operation is performed among the zoom and focus operations is input to the CPU 30, the zoom current limit I _Z indicating the upper limit of the current supplied to the zoom servo system and the focus operation are performed. The focus current limit I _F indicating the upper limit of the current supplied to the focus servo system when only the focus signal indicating that is input to the CPU 30, and the zoom servo system and the focus servo system when both the zoom and focus operation signals are input. The storage device 74 stores the zoom current limit I _Z and the focus current limit I _F indicating the upper limit of the current supplied to each.

For example, the camera current limit value (camera I
If (limit) is set to the limit a, the zoom current limit when only the zoom signal is input is set to I _Z1 . However, I _Z1 is set within a range not exceeding the camera current limit value I _K1 . The focus current limit when only the focus signal is input is I _F1 . However, I _F1
Is set in a range not exceeding the camera current limit value I _K1 .

Input zoom signal and focus signal to both
If the zoom current limit is _Z6, Focus current
I limit_F6It is prescribed. Where I_Z6And I_F6The sum of
Mela current limit I_K1It is set within the range not exceeding. Ma
Also, in this case, set the zoom current limit to the focus current
It is preferable to set it to about twice the mitt and give priority to zoom.
New

Similarly, in each of the limits b, c, d, and e, the zoom current limit when only the zoom signal is input, the focus current limit when only the focus signal is input, the zoom signal and the focus signal are input. The sum current limit and the focus current limit at this time are stored in the storage device 74 in advance as table data.

The CPU 30 uses the select switch 70.
The current limit value input in, the signal indicating whether the extender is in operation, the signal indicating whether zoom operation is in progress (ZOOM
CONT.IN), and a signal (FO
CUS CONT.IN) to recognize what kind of operation is being performed, call the current limit value of each servo system from the storage device 74 in accordance with the operation status, and execute the zoom control circuit 22 and the focus control circuit. A signal defining the current limit is output to each of 42.

FIG. 6 is a flow chart showing a processing flow of the zoom lens control device for the television camera shown in FIG.
First, the CPU 30 recognizes the current limit value input by the select switch 70 (step S601, only step numbers are shown below), and determines whether the current limit is 2 A or more (S602). If the current limit is 2 A or more in S602, all operations such as zoom, focus, and extender are set to the independently operable state and the full servo state (S603).

On the other hand, if it is determined in S602 that the current limit is less than 2 A, it is determined whether or not an extender control signal indicating whether or not the extender has been operated is input (S604). If there is an extender control signal input (EXT.CONT.IN) indicating that the extender has been operated, CPU3
0 outputs a control signal for inhibiting the operation to the zoom control circuit 22 and the focus control circuit 42, respectively, to stop or inhibit the zoom and focus operation (S605). Then, the process returns to S604.

In S604, if there is no extender control signal input (EXT.CONT.IN) indicating that the extender has been operated, then it is determined whether or not there is a zoom signal input (ZOOM CONT.IN). Yes (S6
06). If the zoom operation has not been performed, the presence / absence of a focus signal input (FOCUS CONT.IN) is further determined (S607). If the focus operation has not been performed,
The process returns to S604.

When there is a focus signal input in S607, that is, when only the focus operation is instructed, the CPU 30 obtains the focus current limit for the focus signal input only from the table stored in the storage device 74 ( (S608), the CPU 30 controls the focus control circuit 42 so that the focus operation is performed with the current within the limit range (S609). In this way, the focus operation is executed, and the process returns to S604.

Even if a zoom signal is input in S606, it is subsequently determined whether or not the focus signal is input (S610). If no focus signal is input in S610, it means that only a zoom operation is instructed, and a zoom current limit for only a zoom signal input is obtained from the table stored in the storage device 74 (S611). The CPU 30 controls the zoom control circuit 22 so that the zoom operation is performed with the current within the range (S612). In this way, the zoom operation is executed, and the process returns to S612.

If there is a focus signal input in S610, that is, if both zoom and focus operations are instructed, the zoom limit value and the focus limit value are obtained from the table stored in the storage device 74 (S613). ), So that the zoom operation and the focus operation are performed by the current within the respective limit ranges.
Controls the focus control circuit 42 and the zoom control circuit 22 (S614). Then, the operation corresponding to each operation is executed, and the process returns to S604.

In this way, by detecting the operated object,
Since the current limit is determined for each servo system based on the table stored in the storage device 74 according to the operation status, the current supplied from the camera side can be effectively used. FIG. 7 is a block diagram showing the configuration of another embodiment of the zoom lens control device for a television camera to which the present invention is applied. The same or similar components as those of the television camera zoom lens controller shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

The zoom control circuit 22 is provided with a current detecting means for detecting the current supplied to the zoom operation and notifying the CPU 30 of the detected current value. Further, the zoom control circuit 22 is provided with a voltage varying means so that the voltage applied to the zoom motor 24 can be changed based on a control signal input from the CPU 30. Then, when the zoom signal is input from the zoom signal generating means 20, the zoom control circuit 22 outputs a signal (ZOOM CONT.IN) meaning the zoom signal input to the CPU 3.
0 is notified.

Similarly, the focus control circuit 42 is provided with a current detecting means for detecting the current supplied to the focus operation and notifying the CPU 30 of the detected current value. Further, the focus control circuit 42 is provided with a voltage varying means so that the voltage applied to the focus motor can be changed based on a control signal input from the CPU 30. Then, when the focus signal is input from the focus signal generating means 40, the focus control circuit 42 notifies the CPU 30 of a signal (FOCUS CONT.IN) meaning input of the focus signal.

The CPU 30 uses the select switch 70.
The current limit value input in, the signal indicating whether the extender is in operation, the signal indicating whether zoom operation is in progress (ZOOM
CONT.IN), and a signal (FO
CUS CONT.IN) to recognize what kind of operation is being performed and zoom control circuit 2 according to the operation status
2. Output a signal for controlling the operation of the focus control circuit 42.

FIG. 8 is a flow chart showing a processing flow of the zoom lens control device for the television camera shown in FIG.
The CPU 30 first recognizes the current limit value input by the select switch 70 (step S801, only step numbers are shown below), and determines whether or not the current limit is 2 A or more (S802). If the current limit is 2 A or more in S802, all operations such as zoom, focus, and extender are set to the independently operable state and the full servo state (S803).

On the other hand, if it is determined in S802 that the current limit is less than 2 A, it is determined whether or not an extender control signal indicating whether or not the extender has been operated is input (S804). If there is an extender control signal input (EXT.CONT.IN) indicating that the extender has been operated, CPU3
0 outputs a control signal for inhibiting the operation to the zoom control circuit 22 and the focus control circuit 42, respectively, to stop or inhibit the zoom and focus operation (S805). Then, the process returns to S804.

In S804, if there is no signal input (EXT.CONT.IN) of the extender control signal indicating that the extender has been operated, then it is determined whether or not there is a signal input of the zoom signal (ZOOM CONT.IN). Yes (S8
06). If there is no zoom signal input, it is further determined whether there is a focus signal signal input (FOCUS CONT.IN) (S
807), if there is no focus signal input, the process proceeds to S
Return to 806.

When the focus signal is input in S807, that is, when only the focus operation is instructed, the CPU 30 outputs a control signal for permitting the operation of the focus control circuit 42 and responds to the operation of the focus demand 12. Then, the focusing operation is performed (S808). At this time, the focus control circuit 42 detects the current value I _F during the focus operation and sets the detected current value I _F to CP.
Notify U30 (S809). The CPU 30 compares the detected current value with a preset threshold value, and determines whether the detected current exceeds the threshold value (S810). The threshold value is set to 80% of the camera current limit value input from the select switch 70 and recognized.

When the detected current exceeds the threshold value, C is set so as to reduce the voltage applied to the focusing motor 44.
A signal for controlling the focus control circuit 42 is output from the PU 30. Upon receiving this signal, the focus control circuit 42 controls the voltage varying means to reduce the voltage applied to the focusing motor 44 (S811). As a result, current consumption by the focusing motor 44 is suppressed. Then, the process returns to (a).

If the detected current does not exceed the threshold value in S810, the focusing operation is executed without changing the voltage applied to the focusing motor 44, and the process returns to (a). By the way, even if a zoom signal is input in S806, it is subsequently determined whether or not a focus signal is input (S812). If the focus signal is not input in S812, it means that only the zoom operation is instructed, and the CPU 30 outputs a signal permitting the operation of the focus control circuit 42. Therefore, the zoom operation is performed according to the operation of the zoom rate demand 14 (S813). At this time, the zoom control circuit 22 detects the current value I _Z during the zoom operation and notifies the CPU 30 of the detected current value I _Z (S814).
The CPU 30 compares the detected current value with a preset threshold value and determines whether the detected current value exceeds the threshold value (S815). The threshold may be the same as the threshold described in S810, or different thresholds may be set separately.

When the detected current exceeds the threshold value, the CPU reduces the voltage applied to the zoom motor 24.
A signal for controlling the zoom control circuit 42 is output from 30. Upon receiving this signal, the zoom control circuit 42 controls the voltage varying means to reduce the voltage applied to the zoom motor 24 (S816). As a result, the zoom motor 24
The current consumption due to is suppressed. Then, the process returns to (a). If the detected current does not exceed the threshold value in S815, the zoom operation is executed without changing the voltage applied to the zoom motor 24, and the process returns to (a).

In step S812, when the focus signal is input, that is, when both the zoom and focus operations are instructed, the CPU 30 outputs a signal permitting the operations of both the focus control circuit 42 and the zoom control circuit 22. Each is output, and the focus operation and the zoom operation are performed (S817). At this time, the zoom control circuit 22
Detects the current value I _Z , and the focus control circuit 42 detects the current value I _F (S818). Then, the detected current values I _Z and I _F are notified to the CPU 30.

The CPU 30 sums up the detected current values (I_Z
＋ I_F) Is compared with a preset threshold value and detected.
Sum of current values (I_Z＋ I_F) Exceeds a threshold
Separate (S815). The threshold is the threshold described in S810.
The same value may be used, or another threshold may be set.
Yes. Sum of detected current values (I_Z＋ I_F) Exceeded the threshold
In case of zoom motor and focus motor
To reduce the voltage respectively, zoom control
Signals for controlling the path 22 and the focus control circuit 42 are output.
Is forced. The zoom control circuit 22 receives this signal and
The focus control circuit 42 reduces the voltage applied to the focus control circuit 42.
Receives this signal and reduces the voltage applied to the motor
(S820). As a result, the zoom motor 24 and the zoom motor 24
Current consumption by the focus motor 44 is suppressed. So
After that, the process returns to (a). In S819, the current value
Sum of (I _Z＋ I_F) Does not exceed the threshold, the motor
Zoom operation without changing the voltage applied to the
The focus operation is executed, and the process returns to (a).

In this way, the zoom to be operated is
The current consumed by the focus servo system is detected by the detecting means, and when the current value exceeds a predetermined threshold value, the voltage varying means is controlled to reduce the voltage applied to the current consuming means to reduce the current. Reduce consumption. Thereby, the limited current supplied from the camera side can be distributed to many current consumption means.

In the above embodiment, the combination of zoom, focus, and extender operations has been described as an example, but the present invention is not limited to this, and various operations such as an iris and a PJ lamp provided on a zoom lens for a television camera will be described. Various combinations that limit the operations are possible.
Further, for example, when the current value that can be supplied from the camera side is 10, and the current consumption value of zoom is 8 and the current consumption value of focus is 2, the total current is obtained only by two operations of zoom and focus. The consumption value reaches the limit value. When the iris is further operated in this state, the current consumption value of the zoom may be reduced by lowering the voltage applied to the zoom motor, and the iris may be operated instead.

That is, by limiting the zoom current consumption value to 5, the focus current consumption value to 2, and the iris current consumption value to 3, the limited current is distributed. This reduces the zoom speed but has the advantage that the iris can be used simultaneously.

[0060]

As described above, according to the zoom lens control device for a television camera of the present invention, the current limit different for each camera is recognized by the limit setting means,
If the limit value is smaller than the specified current value, a specific combination of the multiple current consumption means provided on the lens side is not operated at the same time, so that each current consumption means is stable within the limit value range. It is possible to perform the action. Therefore, it is not necessary to provide an auxiliary battery or the like.

In particular, paying attention to the fact that a good image cannot be obtained even if the zoom or focus is operated during the drive of the extender, and regarding the combination of the current consumption means corresponding to the operation which is meaningless to operate simultaneously at the time of photographing. , It is desirable not to operate at the same time. Further, by limiting the upper limit of the current supplied to at least one current consuming means of the plurality of current consuming means and controlling the total current consumption value of the current consuming means to be equal to or less than the limit value, Current can be distributed to various operations.

Further, by detecting the current consuming means to be operated and setting the upper limit of the current value which can be supplied from the camera side for each of the operating objects, each current consuming means is within the range of the limit value. Can be operated stably. Furthermore, the current consumed by the current consuming means that is the target of the operation is detected, and when the current value exceeds a predetermined threshold value, the voltage applied to the current consuming means is reduced to reduce the current consumption. By suppressing, the limited current supplied from the camera side can be distributed to many current consumption means.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a usage mode of a full-servo-operated zoom lens to which a zoom lens control device for a television camera according to the present invention is applied.

FIG. 2 is a block diagram showing a main configuration of a zoom lens control device for a television camera to which the present invention is applied.

FIG. 3 is a flowchart showing a processing flow of a zoom lens control device for a television camera.

FIG. 4 is a block diagram showing a configuration of another embodiment of a zoom lens control device for a television camera to which the present invention is applied.

FIG. 5 is a diagram showing a current limit table stored in a storage device.

FIG. 6 is a flowchart showing a processing flow of a zoom lens control device for a television camera.

FIG. 7 is a block diagram showing a configuration of another embodiment of a zoom lens control device for a television camera to which the present invention is applied.

FIG. 8 is a flowchart showing a processing flow of a zoom lens control device for a television camera.

[Explanation of symbols]

 4 ... Television camera 10 ... Zoom lens for television camera 12 ... Focus demand 14 ... Zoom rate demand 16 ... Viewfinder 20 ... Zoom signal generating means 22 ... Zoom control circuit 24 ... Zoom motor 26 ... Zoom lens group 28, 48 ... Potentiometer 30 ... Central processing unit (CPU) 40 ... Focus signal generation means 42 ... Focus control circuit 44 ... Focus motor 46 ... Moving focus lens group 50 ... Extender signal generation means 55 ... Extender control circuit 56 ... Extender drive motor 60 ... Extender drum 62 ... Position detection sensor 70 ... Camera current limit select switch 74 ... Storage device

Claims (6)

[Claims] 1. A zoom lens for a television camera having a plurality of current consuming means that receives power from a connected camera side and consumes current by performing an operation according to an operation command from a corresponding external operating means. The zoom lens control device for a television camera according to claim 1, further comprising limit value setting means for setting a limit value indicating an upper limit of a current that can be supplied from the camera side. 2. When the limit value set by the limit value setting means is smaller than a predetermined current value,
At least one predetermined one of the plurality of current consumption means
During the operation period of the one or more first current consuming means, there is provided a control means for controlling the current consuming means so as to inhibit the operation of at least one other second current consuming means. The zoom lens control device for a television camera according to claim 1. 3. The control means, when the limit value set by the limit value setting means is smaller than a predetermined current value, the total current consumption value of the plurality of current consuming means is less than or equal to the limit value. 3. The zoom lens controller for a television camera according to claim 2, wherein the upper limit of the current supplied to at least one of the plurality of current consuming means is limited. 4. The control means recognizes the operated current consumption means as an operation target, and the current consumed by the current consumption means does not exceed the limit value input from the limit value setting means. 3. The zoom lens control device for a television camera according to claim 2, wherein the upper limit of the current value that can be supplied from the camera side is limited for each current consumption means that is an operation target. 5. A current detection unit that detects a current consumed by a current consumption unit that is an operation target among the plurality of current consumption units, and a voltage applied to the current consumption unit that is an operation target is changed. And a voltage varying means for controlling the voltage consumption of the current consuming means to be operated when the current value detected by the current detecting means exceeds a predetermined threshold value set in advance. Lowers
3. The zoom lens control device for a television camera according to claim 2, wherein the voltage varying means is controlled so as not to exceed a predetermined upper limit of a current value that can be supplied from the camera side. 6. The first current consumption means is an extender drive means including an extender drive motor for performing an extender operation, and the second current consumption means is a zoom lens drive for performing a zoom operation. 3. A zoom lens control device for a television camera according to claim 2, wherein the zoom lens control device is a zoom drive unit including a focus motor or a focus drive unit including a focus lens drive motor for performing a focus operation.