JPH04204705A - Video camera - Google Patents

Abstract

PURPOSE:To eliminate the need for initialization of the position data of a lens when a power source is off and to allow rapid photographing by providing a memory holding means which maintains the position data stored in a memory means when the power source is off. CONSTITUTION:Whether a zoom lens 2 and a focusing lens 3 exist in reference positions or not is judged in accordance with the outputs from a zoom reference position sensor 12a and a focus reference position sensor 12b. The position data (0,0) is stored in a memory if these lenses exist in the reference positions but the zoom lens 2 is moved and reset to the reference positions by a driving means 5 for variable power and the focusing lens 3 by a driving means 6 for focusing when these lenses do not exist in the reference positions. The lens control at the time of restarting photographing is rapidly executed in this way.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a video camera that eliminates the need to set the initial position of a zoom lens or a focusing lens and enables quick resumption of shooting. Regarding.

(Prior Art) As shown in FIG. 4, recent video camera lens devices include a first group lens 1, a zoom lens 2 for variable power forming a second group lens, and a third group lens. Focusing lens 3 for focusing and C for autofocus
There is a tendency to adopt an inner focus method, which is composed of a CD4 or the like, and focuses by moving the focusing lens 3 without moving the first lens group 1 during focusing.

This is because compared to the front focus method, which focuses by moving the first lens group 1, it has the advantage of being able to focus right up to the front of the lens.

The control system of this inner focus lens device is
As seen in FIG.
3, a memory 14, an arithmetic control means 15, and a variable power driving means 5 and a focusing driving means 6, which are driven by these to move the zoom lens 2 and focusing lens 3; As the variable magnification drive means 5, a foot drive means such as a stepping motor which can be digitally controlled is used.

The reference position detection means 12 includes a zoom reference position sensor 12a for detecting the reference position of the zoom lens 2 and a focus reference position sensor 12b for detecting the reference position of the focusing lens 3. The position of the zoom lens 2 and the position of the focusing lens 3, which is calculated in accordance with the zoom lens position by the calculation control means 15 and brought into focus, are detected by a zoom reference position sensor 12a and a focus reference position sensor 12b. The absolute amount calculated with the reference position as (0, 0), for example, is stored as digital position data (α, β) in the memory 14, which is a storage means, and the position is changed every time the positions of the zoom lens 2 and focusing lens 3 change. Data is updated and stored.

Further, the data table 5a of the arithmetic control means stores the positional relationship between the zoom lens and the focusing lens in the in-focus state using the object distance as a parameter as shown in the characteristic curve in FIG. 6 as position calculation data. and uses it to calculate the position of the focusing lens.

In other words, the distance to the subject is determined by the autofocus means 1.
3, so that the subject distance is, for example, S
If m, the position of the focusing lens relative to the zoom lens position a can be uniquely calculated by using the data table 15a that stores the position calculation data of the characteristic curve as shown in FIG.

Note that autofocus, which is used when the subject is changed or after initialization at the start of shooting, uses the CCD 4 and AF device 10 that constitute the autofocus means 13 to detect the new subject distance and to detect the in-focus position. Then, the focusing drive means 6 is controlled via the arithmetic controller 8115 to drive the focusing lens 3 to the in-focus position and update the position data of the focusing lens. At the same time, the position calculation data in the data table 15a described above is set.

In the conventional video camera having the above configuration, the zoom lens 2 and focusing lens 3 are returned to their respective reference positions prior to the start of image manipulation, and the position data (0, O) is stored in the memory 14 to initialize the data. . Next, the focusing lens 3 is driven by the focusing drive means 6 to the in-focus position of the focusing lens calculated by the calculation control means 15 with respect to the subject distance measured by the autofocus means 13, and the zoom lens 2 is at the reference position. The in-focus position of the focusing lens 3 at that time is set, and the t1 position date is updated. After that, the position of the focusing lens 3 corresponding to the new position indicated by the absolute amount of the zoom lens 2 moved in proportion to the operating plate of the magnification/conversion means 11 is also determined by the characteristic curve shown in FIG. The position of the focusing lens 3 is automatically calculated based on the calculated data, and the position of the focusing lens 3 is set via the focusing drive means 6, and new position data is formed 2 and stored in the memory 14, and this position data is stored in the memory 14. As long as the image is stored in the lens, photographing operations such as zooming and focusing can be easily performed by repeating the above operations.

(Problem to be Solved by the Invention) As described above, when photographing with variable magnification, it is necessary to change the position of the focusing lens in response to the change in the position of the zoom lens. In order to calculate the position of the focusing lens 7 in accordance with the position, it is necessary to constantly store the position data of both lenses, but in conventional video camera lens device control systems, when the power is turned off, the position data of both lenses is stored in the memory 14. Stored position data will be lost. Therefore, it is necessary to return the zoom lens and focusing lens to their respective reference positions and to initialize the position data in the memory each time photography is started. Initializing the position data not only requires extra time and expense, but also requires refocusing after returning to the standard position, and the shooting screen becomes largely blurred until the camera is in focus. There is.

The present invention has been made in view of the F2 point, and is
It is an object of the present invention to provide a video camera that does not require initialization of 1/lens position data during FF operation and enables quick photographing.

(Means for Solving the Problems) In order to achieve the above object, the present invention maintains the function of a storage means for updating and storing positional data of a variable power lens and a focusing lens during shooting, even when the power is turned off. A memory storage means for maintaining the image, and a locking means for prohibiting movement of the variable power lens and the focusing lens when the power is turned off are provided.

Also, immediately before the power is turned off, it is detected whether or not the position data of the variable magnification lens and focusing lens can be stored, and if it is not possible, the
A reference position return means is provided for returning the variable power lens and the focusing lens to their reference positions prior to FF.

Also, when the power is turned on, the presence or absence of position data of the variable power lens and focusing lens stored in the storage means is detected, and if the data is not stored, the variable power lens and focusing lens are returned to their reference positions. An initialization means is provided for initializing the memory by registering the position data (0, 0) at the time of return in the storage means.

A stepping motor is used for at least one of the variable power driving means and the focusing driver, and the position data of the variable power lens and the focusing lens is determined whether the stepping motor is in an unstable stopped state. An unstable stop detection and correction means is provided for detecting and correcting errors in l/lens position and position data that occur due to unstable stop.

Further, a plurality of reference position detection means are provided for each of the zoom lens and the focusing lens, and a reference position update means responsive thereto is provided.

(Function) As described above, since the storage means for storing the position data of the variable power lens and the focusing lens is provided with a memory retention means corresponding to when the power is turned off, when reshooting after the power of the video camera is turned off once, Since the storage means stores the position data immediately before shooting stops, it is possible to immediately resume shooting without returning the zoom lens and focusing lens to their reference positions or initializing the position data in the storage means. I can do it.

Furthermore, the positions of the variable power lens and the focusing lens are held in the stopped state when the position data stored in the storage means is stored by the locking means that operates when the power is turned off.

Furthermore, if the memory holding means does not operate, this can be detected before the power is turned off, and the variable power lens and the focusing lens can be returned to their reference positions by the reference position return means.

Furthermore, when the position data is not stored in the storage means when the power is turned on, the initialization means immediately returns the variable power lens and the focusing lens to their reference positions, and the position data (0, 0 ) can be registered to initialize the memory, then autofocus determines the position (γ) of the focusing lens relative to the subject distance, this position data (0, γ) is stored, and then the arithmetic control means The position calculation data corresponding to the subject distance corresponding to the position data (0, γ) in the data table (Fig. 6 characteristic curve) is specified, and from now on, based on this data, the aircraft image for the same subject is can continue.

In addition, when a stepping motor is used as the variable magnification drive means and the focusing drive means, the unstable stop detection correction means detects the excitation situation (two-phase excitation) that causes the stepping motor to be in an unstable stop state immediately before it stops. However, in that case, before stopping, correct the motor to a stable stopped state and stop the motor, and before restarting shooting, return the motor stop position by the correction to the old position before the correction, which may occur in a non-excited state with the power OFF. Prevents errors caused by discrepancies between lens position and position data due to unstable stopping.

In addition, a plurality of reference position detection means are provided for each of the variable magnification lens and focusing lens, and a reference position update means that operates in response to these means is provided, so even if memory cannot be retained, the shortest distance reference position can be set. You can save time and power by restoring the power.

In addition, if the initialization means confirms that the position data in the memory, which is the storage means, is not stored when the power is turned on, the variable power lens and focusing lens are returned to their reference positions, and the data in the memory is initialized. It will be done.

(Example) The present invention will be explained below based on the drawings.

FIG. 1(a) shows a schematic configuration of a lens device for a video camera according to the present invention, and its configuration is the same as that in FIG. 4. That is, the lens group is composed of a first group lens 1, a zoom lens 2 for variable power, a focusing lens 3 for focusing, an imaging lens, etc., and takes an inner focus type focusing form, and the final part is described later. Autofocus means 13
A solid-state image sensor 4 is provided.

The lens 2 for zooming and the focusing lens 3 for focusing are each provided with driving means 5.6 for zooming and focusing, each of which has a feed screw 30a driven by a foot drive means such as a stepping motor. , 30b, a feed screw type drive mechanism 25a, 25b is provided,
The ends of the feed screws 30a and 30b are provided with a locking means 24 consisting of a zoom lens locking mechanism 24a and a focus lens locking mechanism 24b.

The locking mechanism 24a or 24b, as shown in an enlarged view in FIG. It consists of a locking plate 28 provided on the frame 26 so as to be able to freely suppress it in the direction of the arrow, and a compression spring 29 that biases the locking plate 28 in the direction of the arrow when the electromagnet 27 is not energized. The electromagnet 27 overcomes the biasing force of the compression spring 29 and attracts the locking plate 28 in the direction opposite to the direction of the arrow, thereby stopping the locking function of the locking mechanism 24 with respect to the feed screws 30a and 30b. be. Note that the locking mechanism 24 does not need to be provided if the motor or drive mechanism system constituting the variable power driving means 5 and the focusing driver H6 has sufficient rotation-preventing torque when the power is turned off.

A zoom reference position sensor 12a for setting a reference position is provided on the telephoto side of the zoom lens 2 (to the right in the figure) and on the infinity side (to the right in the figure) of the focusing lens 3.
and a focus reference position sensor 12b, which allows the zoom lens 2 and the focusing lens 3 to
When the reference position for calculating the position of is determined and the zoom lens 2 and focusing lens 3 return to their reference positions, the position data (0, O) is stored in the memory 14 which is a storage means.
Position data obtained by digitizing the absolute amount of movement of the zoom lens 2 and focusing lens 3 with the reference installation as the origin is updated and stored.

Rather than providing only one reference position on the telephoto side of the zoom lens 2 and the infinity side of the focusing lens 3,
With this as the first reference position, a plurality of second, third, etc. reference positions are provided at predetermined distances from the first reference position, and specific reference values are provided corresponding to the distances from each of the first reference positions. , when the lens passes any of the nearest reference positions, the position data may be updated to the specified reference value.

In this case, the lens may be returned to the nearest reference position during initialization. Note that when a plurality of reference positions are provided as described above, a sensor for detecting the reference position is provided for each newly set reference position.

FIG. 2 shows a lens device control system for a video camera according to the present invention.

In the figure, the same reference numerals as in FIG. 5 indicate the same components, and new components not shown in FIG. 5 are a memory backup power supply 21 and a backup power supply voltage detection means 2.
2, a memory holding means 20 comprising a memory W source switching means 23, and a lens locking means 24 comprising a zoom lens locking mechanism 24a, a focus lens locking mechanism 24b, etc.

When the zoom lens 2 and the focusing lens 3 are returned to their respective reference positions, the reference position detection means 12 confirms the return and stores the position data (0, ] in the memory 14 via the CPU 15 which is an arithmetic control means. By doing this, the position data in the memory is initialized.The auto-off signal means 13 performs the initialization of the CCD 4 and AF when the subject is changed.
The new focus position of the focusing lens 3 is detected by the device [10] and the focus drive means 6 is detected via the CPtJ 15.
The absolute amount from the focus reference position is digitized and its movement is instructed, and when it is, for example, the 127th pulse, follllllll) is stored in the memory 14 as position data of the focusing lens 3. In addition, the magnification operation means 11 has a camera operation concept of zoom L.
- The lens 2 is operated each time zooming is performed in order to move it to a desired zooming position, and the CPU 15 uses the operating signal to direct the zooming driving means 5 to digitize the absolute amount from the zoom reference position. The amount of movement is instructed, and position data corresponding to the amount of movement is stored in the memory 14 via the CPL 115 as new position data of the zoom lens 2.

The focusing position of the focusing lens 3 corresponding to the newly set magnification position of the zoom lens 2 is determined by adjusting the focus position of the focusing lens 3, which is stored in advance in the CPL 115 and using the subject distance as a parameter as shown in FIG. Position calculation data is set by the data table 15a indicating the positional relationship with the corresponding focusing lens 3, and the focusing drive means 6 is commanded to move the focusing lens 3 to a new set position, and the corresponding focusing lens 3 is instructed to move to the new setting position. The position data of the lens 3 is also updated and stored in the memory 14.

The memory holding means 20 is a backup power supply voltage detecting means 22.
The power supply voltage of the memory backup power supply 21 is detected by the CPtJ 15 to determine whether or not the memory can be retained. The power source is switched to the memory backup power source 21.

FIGS. 3(A), 3(B), and 3(C) are flowcharts showing the operation of the control system of the video camera according to the present invention;
Figure (a) shows a flowchart when the main power is turned on.

When the main power switch 17 is turned ON and the voltage of the main power supply 9 is applied, the locking of the zoom lens 2 and the focusing lens 3 by the square locking means 24 is released (P
-1), this step is omitted if the stepping motor for driving the lens has sufficient rotation inhibiting torque when the power is turned off.

As will be described later, when the power is turned off, the memory 14 is switched to the memory backup power supply 21, so here the memory power is switched from the backup power supply 21 to the main 11!1i.
)9 (P-2), then it is determined whether the position data of the zoom lens 2 and focusing lens 3 is stored in the memory 14 (P-3), and if it is not stored (P-4). ) to (P-6) initialize the position data. That is, it is determined whether the zoom lens 2 and the focusing lens 3 are at the reference position based on the outputs from the zoom reference position sensor 12a and the focus reference position sensor 12b (P-4), and if they are at the reference position. The position data (0, 0) is stored in the memory 14 (P-6), but when the reference position is not reached, the zoom lens 2 is driven by the variable power driving means 5, and the focusing lens 3 is driven by the focusing driving means. 6 to move and return to the reference position (P-5).

In step (P-3), when it is confirmed that the position data of both lenses are stored in the memory 14, the stepping motor is In order to prevent errors between the positions of the zoom lens and focusing lens and the position data of those lenses, which would be caused by an unstable stop just before the lens stops, one-pulse reverse rotation correction is performed as described later. When the motor is brought to a stable stop,
It is necessary to return the lens position to the old position by rotating the pulse in the normal direction, and this correction (unstable stop detection correction) is performed in steps (P
-7) to (P-10).

That is, the CPU 15 determines (H, L) of the excitation pulses of each phase of the stepping motor output from the driver of the variable power driving means 5 (CP-7), and calculates the relationship between the lens position and position data when the motor is stopped. When a one-pulse reverse correction is performed to eliminate errors, only one pulse is rotated in the forward direction to return the focusing lens 3 to its old position before correction and position it according to the position data stored in the memory 14. (P-8). Next, when the power is turned off for the zoom lens 2, it is determined whether the position correction has been performed to eliminate the error between the lens position and the position data caused by the unstable stop in the same way as described above (P-9). When performing reverse correction, the zoom lens 2 is returned to the old position before correction by one pulse of 1-2 phase excitation and placed in accordance with the position data stored in the memory 14 (P-10). . Thereafter, the process shifts to AF sub-control or zoom control, but its operation is the same as before and has no relation to the present invention, so a flowchart will be omitted.

Note that the method for determining whether or not the memory 14 stores position data in step (P-3) is as follows.
There is a method of determining based on the voltage level of the memory backup power supply 21, or a method of inputting a specific code when storing data and determining that it is abnormal if the code is not output correctly when reading data. However, in this case, replace the backup power supply 21 while the device is powered off, and when the voltage is restored, reset the internal memory so that the specific code will not be output and confirm that no position data is stored. Make it.

FIG. 3(b) is a Relow chart for updating position data when a plurality of reference positions are provided.

Now, in the zooming operation, a predetermined pulse is applied to the stepping motor by the zooming driving means 513 and the focusing driving means 6 according to a command from the CPU 15 to drive the motor (Q-1), and the zoom lens is stored in the memory 14. 2 and focusing lens 3 are stored (Q-2). Then, when zooming and focusing are further continued by variable magnification operation, the lenses are stored in the second, third, etc.
- A reference position detection sensor 12a provided at a new reference position detects whether or not the new reference position has been reached.

12b is detected Q-3), and when the lens position data is at the new reference position, it is determined whether the lens position data has been updated to the new reference position data Q-4), and if it has not been updated accordingly Update the settings to the new reference position data (Q-5).

FIG. 3(c) shows a flowchart when the main power is turned off. The memory backup voltage detection means 22 detects the voltage of the memory backup power supply 21 and determines whether memory retention is possible (R-1). As a result, if it is determined that memory retention is not possible, the zoom lens 2 is adjusted by the reference position return means.
Then, the focusing lens 3 is returned to the reference position (R-2), and when it is determined that the memory can be retained, the position data of both lenses immediately before stopping and whether the stepping is stable or unstable are stored in the memory 14. Store state data indicating the excitation state of R-3), and then check whether the stopping position of the stepping motor, which is the stepping motor of each driving means 5 and 6 for zooming and focusing, is at a stable stopping position. It is judged whether or not (r
(-4), when it is determined that it is in an unstable state, for example, in the case of a 4-phase stepping motor, when it stops in a 2-phase excitation state, it becomes an unstable stop state, so in this case, 1-
Correct the reverse rotation by one pulse with two-phase excitation to bring it to a stable stop state (R-5). Then, switch the memory power source from the main IT source 9 to the memory backup power source 21 by the memory power source switching means 23 & 23 (R-5). 6). Thereafter, the lens locking means 24 is activated and the main power source 9 is turned off. In step (R-4), the detection means for detecting the unstable stop state of the stepping motor is the excitation state e H,, i, + of each phase coil output from the stepping motor driver. The state data is shown as 5, and the judgment is made in CPtJ15.

(Effects of the Invention) As explained above, in the present invention, the storage means for storing the position data indicating the positions of the variable power lens and the focusing lens retains the position data even when the power is turned off. Since the lens locking means prohibits the lens from moving when the power is turned off, the lens position data immediately before the power is turned off is retained, and the position of the lens remains unchanged until the next shooting. Since the data is retained exactly as it is, it is possible to quickly control the single lens when restarting shooting after a shooting interruption, and there is no need to initialize the lens.
It is possible to eliminate blurring of the image until the image is focused, the continuity of the aircraft image is not impaired, and wasteful power consumption for initialization can be eliminated.

In addition, it was found that the one-step return to the reference position prevents memory retention immediately before the power is turned off.
When it is found that the lens position data is not stored in the memory after N, the zoom 1 lens and focusing lens automatically return to the reference position, and in the latter case, the position data is initialized after returning to the reference position. Do this.

In addition, an unstable stop of the lens is detected in advance based on the excitation status of a progressive motor such as a stepping motor just before the stop, and the lens is stopped in a stable stop state immediately before the stop, and the power supply is then turned off.
Since the correction is made at the time of N, an error between the lens position and the position data can be prevented from occurring.

Furthermore, since the reference position of the lens is not limited to one but a plurality of locations, it is only necessary to install the reference position updating means to return the lens to the reference position of the shortest movement distance during initialization, which is economical.

[Brief explanation of the drawing]

FIG. 1(A) is a schematic configuration diagram of a lens device of a video camera according to the present invention, FIG. 1(V) is a schematic side view of a locking mechanism,
FIG. 2 is a block diagram of the control system of the lens device of the video camera according to the present invention, and FIG. 3 is a flowchart showing the operation of the control system of the video camera according to the present invention. B) is a flowchart showing the lens reference position updating means, (C) is a flowchart when the power is turned off, FIG. 4 is a schematic configuration diagram of a conventional video camera lens device, and FIG. 5 is the lens shown in FIG. FIG. 6, which is a block diagram of the control system of the apparatus, is a characteristic curve showing the relationship between the position of the focusing lens and the position of the variable power lens of the inner focus type lens apparatus, with the object distance as a parameter.

Claims (7)

[Claims] (1) A driving means for stepwise driving at least one movable lens for magnification change or focusing, and a position of the stepwise driven lens from a reference position as position data. What is claimed is: 1. A video camera comprising a storage means for storing position data, the video camera comprising a storage means for maintaining the position data stored in the storage means when the power is turned off. (2) The video camera according to claim 1, further comprising a lens locking means for prohibiting movement of the progressively driven lens when the power is turned off. (3) The memory holding means comprises a backup power source, voltage detection means for the backup power source, and power supply switching means for switching the power source of the storage means from the main power source to the backup power source when the power is turned off. video camera. (4) Detect whether or not the memory retention means can retain the position data in the storage means, and if the memory retention is not possible, return the variable magnification lens and focusing lens to their respective reference positions before turning off the power. 2. The video camera according to claim 1, further comprising reference position return means for returning to a reference position. (5) The storage means detects whether position data is stored when the power is turned on, and if the position data is not stored, returns the variable power lens and focusing lens to their reference positions and initializes the storage means. The video camera according to claim 1, further comprising initialization means for. (6) The driving means has a stepping motor, and detects an unstable stopping state of the stepping motor based on the driver output of the stepping motor immediately before the stepping motor stops, and when the stepping motor is in an unstable state, a lens is generated due to the unstable stopping state. The video camera according to claim 1, further comprising unstable stop detection and correction means for correcting errors between positions and position data. (7) A plurality of reference positions are provided for the variable power lens and the focusing lens, and reference position updating means updates the position data stored in the storage means when the lens reaches the reference position. The video camera according to claim 1.