JP3298872B2 - Imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A Industrial Field of Use B Outline of the Invention C Prior Art D Problems to be Solved by the Invention E Means for Solving the Problems F Operation G Example H Effects of the Invention A Field of Industrial Use The present invention relates to: It has a zoom lens system that allows the movable focusing lens to move in the optical axis direction according to the displacement of the movable variable magnification lens in the optical axis direction, and image light from a subject through the zoom lens system is made to enter the image pickup unit to capture an image. The present invention relates to an imaging device capable of obtaining an output signal.

B. Summary of the Invention In the present invention, a movable variable power lens and a movable focusing lens are arranged with a common optical axis direction, and the movable focusing lens moves in the optical axis direction according to the displacement of the movable variable magnification lens in the optical axis direction. When the movable variable-magnification lens is moved in an imaging apparatus that has a zoom lens system that is supposed to be illuminated, and in which image light from a subject through the zoom lens system is made incident on the imaging unit and an imaging output signal is obtained. ,
The position of the movable zoom lens is detected based on the moving direction of the movable zoom lens stored in the storage unit immediately before the stationary state and the displacement of the movable zoom lens at that time, and the movable focusing lens detects the position. In addition to taking the position corresponding to the position of the movable zoom lens, when the power is turned on,
After moving the movable variable power lens in a predetermined direction by a predetermined distance, the movable variable power lens is stopped, and the preset direction is stored in the storage means so as to be initially set as the moving direction immediately before the movable variable power lens is in the stationary state. By doing so, the position of the movable focusing lens can be made to properly follow the initial displacement of the movable variable power lens after the power is turned on.

C Prior Art In an imaging apparatus such as a video camera connected to a video tape recorder (VTR) and used, image light from a subject is made to enter an imaging unit through a lens system, and the subject is placed on an imaging surface of the imaging unit. Although an image is projected, a zoom lens system is generally used as a lens system so that the magnification of a subject image projected on an imaging surface can be continuously changed within a predetermined range. It is a target.
A zoom lens system used in such an image pickup apparatus, for example, as shown in FIGS. 3A, 3B, and 3C, is sequentially arranged from the object side to the image pickup unit 12 side with a common optical axis in the lens barrel 11. The zoom lens includes a front lens 13, a variable power lens 14, a correction lens 15, a relay lens 16, and a focusing lens 17. Each of the front end lens 13 and the relay lens 16 has a fixed position with respect to the lens barrel 11,
On the other hand, each of the variable power lens 14, the correction lens 15, and the focusing lens 17 is to be moved along the optical axis with respect to the lens barrel 11.

The variable power lens 14 is a movable one that can be moved along the optical axis within a preset range between the front end lens 13 and the correction lens 15 manually or by a predetermined driving means, Zooming is performed by continuously changing the magnification of the subject image projected on the imaging unit 12 within a preset range. Further, the correction lens 15 moves within a preset range between the variable power lens 14 and the relay lens 16 along the optical axis along the variable power lens 14.
Are moved along with the movement of the image, and the image magnification is corrected. Further, when the magnification of the subject image projected on the imaging unit 12 is continuously changed by the movement of the zoom lens 14, the focusing lens 17
In order to maintain the subject image projected above in an appropriate focus state irrespective of the change in magnification, a predetermined range between the relay lens 16 and the imaging unit 12 is set according to the movement of the variable power lens 14. Are movable along the optical axis.

In such a zoom lens system, for example,
As shown in FIGS. A, B, and C, when the subject image projected on the imaging unit 12 is a wide-angle image with respect to the subject 18 positioned at a distance L from the front end lens 12, the third As shown in FIG. A, the variable power lens 14 moves within the movement range toward the front end lens 13, and moves away from the front end lens 13.
Dv takes a position where it is assumed to be short.Accordingly, the correction lens 15 takes a position on the relay lens 16 side within the moving range, and the focusing lens 17 moves the moving range to the imaging unit 12 side. The user moves to take a position where the distance Dm from the imaging unit 12 is short. Further, when the subject image projected on the imaging unit 12 is an intermediate magnification image for the subject 18 whose position is L from the front end lens 13, as shown in FIG. 3B,
The variable power lens 14 takes a position at the center of the moving range and the distance Dv from the front end lens 13 is of an intermediate length, and accordingly, the correcting lens 15 is moved to the center position within the moving range. And the focusing lens 17 is positioned at the center of the
At a position where the distance Dm from the object is of an intermediate length. Further, when the subject image projected on the imaging unit 12 is a telephoto image of the subject 18 at a position at a distance L from the front lens 13, as shown in FIG. Double lens 14 is a correction lens within its moving range
Move to the 15 side, take a position where the distance Dv from the front end lens 13 is long, and accordingly, the correction lens 15
While taking a position slightly closer to the relay lens 16 than the center in the movement range, the focusing lens 17 moves to the relay lens 16 side in the movement range, and the imaging unit 12
The distance Dm is set to be long.

When zooming is performed in this manner, the focusing lens 17 is adjusted according to the position of the zoom lens 14 in order to maintain the subject image projected on the imaging unit 12 in an appropriate focus state regardless of a change in magnification. As for the position to be taken, the relationship between the position of the variable power lens 14 and the position of the focusing lens 17 to be taken to maintain the subject image projected on the imaging unit 12 in an appropriate focus state is set in advance, and The relationship is set by comparing the actual position of the variable power lens 14 with the relationship. Therefore, it is necessary to detect the position of the variable power lens 14 in the lens barrel 11,
Therefore, in general, a potentiometer in which the displacement of the variable power lens 14 is transmitted and moved via the gear mechanism is arranged in the lens barrel 11, and the position of the variable power lens 14 in the lens barrel 11 is changed by the output change of the potentiometer. As required.

However, since the gear mechanism that transmits the displacement of the variable power lens 14 to the potentiometer involves play in the engaging tooth surface, when the variable power lens 14 is shifted from the stationary state to the moving state, When the previous moving direction and the new moving direction are the same and opposite,
The transmission state of the displacement to the potentiometer will be different, and therefore, in order to properly detect the position of the variable power lens 14 shifted from the stationary state to the moving state, not only the displacement after shifting to the moving state but also the displacement The direction of movement immediately before the stationary state is required. Therefore, in order to detect the position of the variable power lens 14, every time the variable power lens 14 takes a stationary state, it is considered that the moving direction immediately before the variable power lens 14 is stored and stored in the storage means.

D Problems to be Solved by the Invention As described above, the variable power lens 14 and the focusing lens
In order to detect the position of the variable power lens 14 required for setting the position to be taken by the focusing lens 17 in the imaging apparatus provided with the zoom lens system including In the case where the immediately preceding movement direction is stored and held in the storage means, if the power supply of the apparatus is cut off, the contents stored in the storage means are erased, and thereafter the power supply is turned on. At the time of the first displacement of the variable power lens 14 after the power is turned on, the moving direction immediately before the stationary state is unknown, and the position of the variable power lens 14 cannot be correctly detected. As a result, the focusing lens There is a disadvantage that it takes a long time for the zoom lens 17 to take an appropriate position corresponding to the displacement of the variable power lens 14.

In view of such a point, in the present invention, a movable variable power lens and a movable focusing lens are arranged with a common optical axis direction,
It has a zoom lens system in which the movable focusing lens is moved in the optical axis direction according to the displacement of the movable variable magnification lens in the optical axis direction, and image light from a subject through the zoom lens system enters the imaging unit The movable focusing lens is adjusted according to the position of the movable zoom lens to maintain the subject image projected on the imaging unit in the proper focus state regardless of the change in magnification. The position to be taken depends on the relationship between the position of the movable zoom lens and the position of the movable focusing lens, which is set in advance to maintain the subject image projected on the imaging unit in an appropriate focus state. The first displacement of the movable zoom lens after turning on the power is set by collating the position of the movable zoom lens detected at , The position of the movable lens is properly detected, and an object thereof is to provide an imaging apparatus that the position of the movable focusing lens is adapted to be brought properly follow.

E Means for Solving the Problems In order to achieve the above object, an imaging apparatus according to the present invention comprises:
A zoom lens system including a movable variable-power lens and a movable focusing lens; an imaging unit that receives image light from a subject through the zoom lens system and obtains an imaging output signal of the subject; A first lens driving unit for moving the magnification lens in a direction along the optical axis; and a slider that is moved by transmitting the movement of the movable variable magnification lens, and is movable based on the movement of the slider. Detecting means for detecting the moving direction and displacement of the variable power lens, second lens driving means for moving the movable focusing lens in a direction along its optical axis, and when the movable variable lens is moved from the moving state to the stationary state. A moving direction storage control means for storing in a storage means a moving direction of the movable variable power lens immediately before the stationary state detected by the detecting means, and a movable variable power lens when the movable variable power lens is moved. The position of the movable zoom lens is detected based on the moving direction of the movable zoom lens stored in the storage state immediately before the stationary state and the displacement detected by the detection unit, and the detected movable lens is moved to the movable focusing lens. Drive control means for operating the second lens drive means to take a position corresponding to the position of the variable power lens, and further comprising, when power is turned on, moving the movable variable power lens in a predetermined direction. In addition to operating the first lens driving means to stop after moving by the distance of, the preset direction in which the movable variable-power lens is moved is initially set as the moving direction immediately before the movable variable-power lens is at rest. The moving direction initial setting means for storing the moving direction in the storage means is provided and configured.

In the imaging apparatus according to the present invention configured as described above, when the movable variable magnification lens is shifted from the stationary state to the moving state, the movable focusing lens is moved to the position appropriately following the displacement of the movable variable magnification lens. The position of the movable variable power lens, which is required to take the
It is performed based on the displacement detected by the detecting means, but when the power is turned on, the movable variable power lens is moved after a predetermined distance in a preset direction and then stopped, and at that time, Since the preset direction in which the movable variable magnification lens is moved is initially set as the moving direction immediately before the movable variable magnification lens comes to a stationary state, the initial displacement of the movable variable magnification lens after the power is turned on is also changed. The position of the magnification lens is properly detected, and accordingly, the position of the movable focusing lens is properly followed. Therefore, it is assumed that the imaging output signal obtained from the imaging unit is always formed under the condition that the subject image projected on the imaging unit is maintained in an appropriate focus state regardless of a change in magnification. Become.

G Embodiment FIG. 1 shows an example of an imaging apparatus according to the present invention.

In the example shown in FIG. 1, a zoom lens system 21 and an image pickup unit 22 are disposed in a lens barrel 20, and the lens barrel 20 has a tip 20a directed toward a subject. Is incident on the imaging unit 22 through the zoom lens system 21, and a subject image is projected on the imaging unit 22. The zoom lens system 21 includes a front end lens 23, a movable zoom lens 24, a movable correction lens 25, and a relay, which are sequentially arranged in the lens barrel 20 from the tip end 20a side to the imaging unit 22 side with a common optical axis. It is configured to include a lens 26 and a movable focusing lens 27. The positions of the front end lens 23 and the relay lens 26 are fixed with respect to the lens barrel 20. On the other hand, the movable zoom lens 24, the movable zoom lens 25, and the movable focusing lens Each of the 27 is a lens barrel
With respect to 20, the position is to be moved along the optical axis.

The movable variable power lens 24 is moved by the variable power lens driving mechanism 30 provided in the lens barrel 20 to the front end lens 23 and the movable variable power lens.
25 is moved within a preset range between 25 and 25, thereby performing zooming by continuously changing the magnification of the subject image projected on the imaging unit 22 within the preset range. It is said. In addition, movable variable power lens 25
The movable variable magnification lens is moved along the optical axis within a preset range between the movable variable magnification lens 24 and the relay lens 26 by the correction lens driving mechanism 31 provided in the lens barrel 20.
It is moved along with the movement of 24, and corrects the image magnification. In addition, a movable focusing lens
Reference numeral 27 denotes an image pickup unit which is moved by moving a movable variable power lens 24 by a focusing lens driving mechanism 32 provided in the lens barrel 20.
When the magnification of the object image projected on the imaging unit 22 is continuously changed, the movable variable magnification lens 24 is maintained in order to maintain the object image projected on the imaging unit 22 in an appropriate focus state regardless of the change in magnification. Relay lens according to the movement of
Within the preset range between 26 and the bill image section 22,
It is moved along the optical axis.

Further, within the lens barrel 20, a variable power lens displacement detection unit 33 provided in connection with the movable variable power lens 24 and a focusing lens displacement detection unit 34 provided in connection with the movable focusing lens 27 are provided. I have. Variable-lens displacement detector
Reference numeral 33 denotes a potentiometer having a slider which is moved by the variable power lens driving mechanism 30 and is transmitted through a gear mechanism to move the variable power lens 24. Based on the movement of the moving element, the displacement of the movable variable power lens 24 in the lens barrel 20 is detected with a distance DV from the position of the fixed front end lens 23, and a detection output signal SPV representing the detected distance DV is transmitted. I do. From the detection output signal SPV, not only the displacement amount of the movable zoom lens 24 but also the moving direction of the movable zoom lens 24 can be obtained. That is, the variable magnification lens displacement detection unit
Reference numeral 33 denotes a detecting means for detecting the moving direction and the displacement of the movable variable power lens 24 based on the movement of the slider of the potentiometer. The focusing lens displacement detection unit 34 detects that the movement of the movable focusing lens 27 moved by the focusing lens drive mechanism 32
A potentiometer having a slider transmitted and moved via a gear mechanism is used, and the displacement of the movable focusing lens 27 in the lens barrel 20 is imaged based on the movement of the slider of the potentiometer. It detects with the distance DM from the position 22 and sends out a detection output signal SPM indicating the detected distance DM. Each of the detection output signal SPV obtained from the variable power lens displacement detection unit 33 and the detection output signal SPM obtained from the focusing lens displacement detection unit 34 is supplied to the control block 40.

The imaging unit 22 includes, for example, a solid-state imaging device using a charge-coupled device (CCD), performs photoelectric conversion on a subject image projected thereon, and outputs an imaging output signal Si corresponding to the subject image. Is sent. Then, the imaging output signal Si obtained from the imaging unit 22 is supplied to the video signal forming unit 35, and the imaging signal forming unit 35 forms a video signal Sv based on the imaging output signal Si, and outputs it to the video signal output terminal 38. Is derived.

The control block 40 includes a power-on signal SB transmitted from a power-on signal supply unit 36, which is generated when the power to the apparatus is turned on, and a zoom lens system 21 transmitted from a zooming command signal forming unit 37. Zooming command signal SZ indicating that zooming should be performed
Is also supplied. Then, the control block 40 detects the position of the movable variable power lens 24, the movable correction lens 25, and the movable focusing lens 27,
A power-on signal transmitted from a power-on signal supply unit 36 includes a moving direction initial setting unit 41 for performing movement control and the like, a drive control unit 42, a moving direction storage control unit 43, and a memory 44. SB, the detection output signal SPV obtained from the variable power lens displacement detection unit 33, the detection output signal SPM obtained from the focusing lens displacement detection unit 34, and the zooming command signal SZ supplied from the zooming command signal forming unit 37
In accordance with the like, a variable-magnification lens initialization control signal CV1, a variable-magnification lens drive control signal CV, a correction lens drive control signal CC, and a focusing lens drive control signal CM are formed. 45, correction lens drive circuit 4
6 and supply it to the focusing lens drive circuit 47. The memory 44 includes a movable variable power lens 24 that should be taken to maintain a subject image projected on the imaging unit 22 in focus regardless of a change in magnification when zooming in the zoom lens system 21 is performed. A lens position data map representing the relationship between the position and the position of the movable focusing lens 27 is stored.

The variable power lens drive circuit unit 45 forms an initialization drive signal SDIv based on the variable power lens initialization control signal CVI and supplies it to the variable power lens drive mechanism 30, and is based on the variable power lens drive control signal CV. A drive signal SDv is formed and supplied to the variable power lens drive mechanism 30, and the variable power lens drive mechanism 30 is operated according to the variable power lens initialization control signal CVI or the variable power lens drive control signal CV, and the movable variable power The magnification lens 24 is moved in a direction along the optical axis. In addition, the correction lens drive circuit unit 46 generates a drive signal based on the correction lens drive control signal CC.
Form SDc and supply it to the correction lens drive mechanism 31,
The correction lens driving mechanism 31 is operated to move the movable correction lens 25 in a direction along the optical axis. Further, the focusing lens drive circuit 47 forms a drive signal SDm based on the focusing lens drive control signal CM, supplies it to the focusing lens drive mechanism 32, activates the focusing lens drive mechanism 32, and drives the movable focusing lens 27. It is moved in a direction along the optical axis.

Under such circumstances, when the power of the apparatus is turned on and the power-on signal SB is supplied from the power-on signal supply unit 36 to the control block 40 accordingly, the moving direction initial setting unit 41 in the control block 40 Operates in response to the power-on signal SB,
The variable-magnification lens initialization control signal CVI is used to change the magnification
Send to 5. As a result, the initialization drive signal SDIv is supplied from the variable power lens driving circuit 45 to the variable power lens driving mechanism 30, and the variable power lens driving mechanism 30 moves the movable variable power lens 24 to the front end lens 23 along the optical axis. Moved in the direction to go. In such a case, the variable power lens initialization control signal CVI is set so that the movable variable power lens 24 moves in the direction toward the front end lens 23 accordingly.

Further, at this time, the movement direction initial setting means 41 receives the detection output signal SPV obtained from the variable power lens displacement detection unit 33, and the detection output signal SPV detects the displacement of the movable variable power lens 24 which is substantially equal to or more than the minimum unit. When it indicates, the transmission of the variable power lens initialization control signal CVI to the variable power lens drive circuit unit 45 is stopped. As a result, the zoom lens drive circuit 45
Then, the supply of the initialization drive signal SDIv to the variable power lens driving mechanism 30 is stopped, and the movable variable power lens 24 is set in a stationary state.

Then, the moving direction initial setting means 41 stores data representing the moving direction toward the front end lens 23 into the movable variable power lens 24.
Is supplied to the memory 44 as initial data relating to the moving direction immediately before the stationary state, and is stored in the memory 44. Thus, when the power of the apparatus is turned on, the moving direction of the movable variable power lens 24 immediately before the stationary state is initialized with the direction toward the front end lens 23, and is stored in the memory.
It will be stored in 44.

Thereafter, when the zooming command signal SZ from the zooming command signal forming unit 37 is supplied to the control block 40, the drive control means 42 operates in response to the zooming command signal SZ, and drives the zoom lens according to the zooming command signal SZ. The control signal CV is sent to the variable magnification lens drive circuit 45. As a result, the drive signal SDv is supplied from the variable power lens driving circuit unit 45 to the variable power lens driving mechanism 30, and the variable power lens driving mechanism 30 moves the movable variable power lens 24 along its optical axis, thereby achieving zooming. To be done. The supply of the zoom lens drive control signal CV to the zoom lens drive circuit unit 45 and the movement of the movable zoom lens 24 based on the supply of the zoom lens drive control signal CV continue during the period when the zooming command signal SZ is supplied to the control block 40. Is done.

Further, at this time, the drive control means 42 receives the detection output signal SPV obtained from the variable power lens displacement detection unit 33, and stores the displacement of the movable variable power lens 24 represented by the detection output signal SPV and the memory 44, The position of the movable zoom lens 24 is detected based on the moving direction immediately before the stationary state before the movable zoom lens 24 is moved. The drive control means 42 detects the position of the movable variable power lens 24 based on the displacement of the movable variable power lens 24 and the moving direction immediately before the stationary state before the moving state, and a known method is used. Done. Then, a correction lens drive control signal CC corresponding to the detected position of the movable variable power lens 24 is formed, and it is supplied to the auxiliary lens drive circuit 46, and the movable correction lens 25 is moved by the correction lens drive mechanism 31. The movable compensating lens 25 makes a correction according to the movement of the movable variable-magnification lens 24 by setting the movable compensating lens 25 in a state of being moved in a direction along the optical axis.

Further, the drive control unit 42 checks the detected position of the movable variable power lens 24 against the lens position data map stored in advance in the memory 44 as described above, and After the position of the movable focusing lens 27 corresponding to the position is set as a target position, a focusing lens drive control signal CM is sent to the focusing lens drive circuit unit 47. As a result, the driving signal SDm is supplied from the focusing lens driving circuit 47 to the focusing lens driving mechanism 32, and the movable focusing lens 27 is moved along the optical axis by the focusing lens driving mechanism 32. Then, the movement control means 42
At this time, receiving the detection output signal SPM obtained from the focusing lens displacement detection unit 34, the position of the movable focusing lens 27 is detected based on the displacement of the movable focusing lens 27 represented by the detection output signal SPM, and the position of the movable focusing lens 27 is set. When the target position is reached, the transmission of the focusing lens drive control signal CM to the focusing lens drive circuit 47 is stopped. In such a case, the detection of the position of the movable focusing lens 27 by the drive control means 42 is performed in the same manner as in the case of detecting the position of the movable variable lens 24. As a result, the supply of the drive signal SDm from the focusing lens drive circuit section 47 to the focusing lens drive mechanism 32 is stopped, and the movable focusing lens 27 assumes the target position.

Such position control of the movable focusing lens 27 is performed while the movable variable power lens 24 is moving.
Is continuously performed so as to follow the displacement of the variable magnification lens 24, and as a result, the imaging unit is moved by the zoom lens system 21.
The subject image projected on 22 is kept in focus regardless of the change in the magnification. Also, while the position control of the movable focusing lens 27 is being performed, the control block
The movement direction storage control means 43 in 40 receives the detection output signal SPV obtained from the variable magnification lens displacement detection unit 33.

Then, thereafter, when the supply of the zooming command signal SZ to the control block 40 is stopped and the movable variable power lens 24 is shifted from the moving state to the stationary state, the moving direction storage control unit 43 receives the change received up to that time. Double lens displacement detector 33
Based on the detection output signal SPV from the
Of the movable variable magnification lens 24 is supplied to the memory 44 and stored in the memory 44.
As a result, the moving direction of the movable variable magnification lens 24 immediately before the stationary state is stored in the memory 44, and the stored moving direction is movable by the drive control unit 42 when the next zooming is performed. It is used when the position of the variable power lens 24 is detected.

As described above, the movable focusing lens 27 is moved in accordance with the movement of the movable variable power lens 24, so that the subject image in the imaging unit 22 by the zoom lens system 21 is maintained in a focused state. Zooming for continuously changing the magnification of the subject image in 22 within a predetermined range is performed.

Next, the moving direction initial setting means in the control block 40
FIG. 2 is a flowchart showing an example of a program executed at the time when the power of the apparatus is turned on and the moving direction of the movable variable power lens 24 immediately before the stationary state is set as described above with reference to the flowchart shown in FIG. State.

In executing the program represented by the flowchart shown in FIG.
In step 51, the power-on signal SB and the detection output signal SPV are fetched, and in the following step 52, it is determined whether or not the power-on signal SB from the power-on signal supply unit 36 has arrived. As a result, if the power-on signal SB has not arrived, the process returns to step 51. On the other hand, if the power-on signal SB has arrived, in step 53, the variable power lens initialization control signal CVI is changed. Double lens drive circuit 45
Start sending to. Thus, the variable power lens 24 is moved by the variable power lens drive mechanism 30 in the direction toward the front lens 23 along the optical axis.

Next, in step 54, the variable power lens displacement detection unit 33
It is determined whether or not the detection output signal SPV has changed so as to indicate a displacement of the movable variable power lens 24 substantially equal to or more than the minimum unit. If the detection output signal SPV has not changed, the process returns to step 51. If the result of the determination in step 54 shows that the detection output signal SPV has changed to indicate a displacement of the movable variable power lens 24 that is substantially equal to or more than the minimum unit, in step 55, the variable power lens initialization control signal CVI To the zoom lens drive circuit 45 is terminated. As a result, the movable variable power lens 24 is stopped and is brought into a stopped state.

Thereafter, in step 56, data representing the moving direction of the movable variable power lens 24 toward the front end lens 23 is supplied to the memory 44 as initial data relating to the moving direction immediately before the movable variable power lens 24 is at rest, and It is memorized, and it returns to step 51.

H Effects of the Invention As is clear from the above description, in the imaging apparatus according to the present invention, when the movable variable power lens is moved,
The position of the movable zoom lens is detected based on the moving direction of the movable zoom lens stored in the storage unit immediately before the stationary state and the displacement detected by the detection unit, and the detected movable zoom lens is detected by the movable focusing lens. Drive control means for operating the second lens drive means to take a position corresponding to the position of the magnification lens, and when power is turned on, move the movable variable magnification lens by a predetermined distance in a preset direction. A moving direction initial setting means for operating the first lens driving means to stop after the moving direction, and for storing in a storage means for initial setting a preset direction as a moving direction immediately before the stationary state of the movable variable power lens. As a result, an effect unique to the present invention can be obtained. That is, when the power is turned on by the moving direction initial setting means, the movable variable power lens is stopped after moving a predetermined distance in a predetermined direction, and at that time, the movable variable power lens is moved. The set direction is initially set as the moving direction immediately before the stationary state of the movable variable power lens, and based on the moving direction stored in the storage means and the displacement detected by the detecting means, by the drive control means. Since the position of the movable variable-power lens is detected, the position of the movable variable-power lens is properly detected even when the movable variable-power lens is first displaced after the power is turned on. Then, the second lens driving means is operated by the drive control means to cause the movable focusing lens to take a position corresponding to the position of the movable variable magnification lens detected properly. It is assumed that the position of the movable focusing lens appropriately follows the position of the movable variable-power lens even when the first lens is displaced. As a result, the imaging output signal obtained from the imaging unit is always formed under the condition that the subject image projected on the imaging unit is kept in focus regardless of the change in magnification. it can.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of an imaging apparatus according to the present invention, and FIG. 2 is a view showing an example in which a moving direction initializing means incorporated in a control block in the example shown in FIG. FIG. 3 is a flowchart showing an example of a program executed when initializing the moving direction immediately before the stationary state of the magnification lens, and FIGS. 3A, 3B and 3C are schematic structural views provided for explaining a zoom lens system. In the figure, 20 is a lens barrel, 21 is a zoom lens system, 22 is an imaging unit, 23
Is a front end lens, 24 is a movable variable magnification lens, 25 is a movable correction lens, 27 is a movable focusing lens, 30 is a variable magnification lens driving mechanism, 31 is a correction lens driving mechanism, 32 is a focusing lens driving mechanism, and 33 is a variable magnification lens. Displacement detecting unit, 34 is a focusing lens displacement detecting unit, 35 is a video signal forming unit, 36
Is a power-on signal supply unit, 37 is a zooming command signal forming unit, 40 is a control block, 41 is a moving direction initial setting unit, 42
Is a drive control means, 43 is a movement direction storage control means, 44 is a memory, 45 is a variable magnification lens drive circuit section, 46 is a correction lens drive circuit section, and 47 is a focusing lens drive circuit section.

Claims (1)

(57) [Claims] A zoom lens system including a movable variable-power lens and a movable focusing lens; image light from a subject passing through the zoom lens system is incident; An imaging unit obtained, a first lens driving unit for moving the movable variable power lens in a direction along the optical axis, and a slider to which the movement of the movable variable power lens is transmitted and moved, Detecting means for detecting the moving direction and displacement of the movable variable magnification lens based on the movement of the slider; second lens driving means for moving the movable focusing lens in a direction along its optical axis; When the variable power lens is changed from the moving state to the stationary state, the moving direction storage for storing the moving direction immediately before the stationary state of the variable power variable lens detected by the detection means in the storage means. Control means; and when the movable variable power lens is moved, the movable movable lens is stored in the storage means based on a moving direction immediately before the stationary state of the movable variable lens and a displacement detected by the detection means. A drive control means for detecting a position of the variable power lens, operating the second lens driving means to cause the movable focusing lens to take a position corresponding to the detected position of the movable variable lens, When the lens is inserted, the movable lens is moved by a predetermined distance in a predetermined direction and then the first lens driving means is operated to stop the lens. A moving direction initial setting means for storing the moving direction in the storage means so as to initialize the moving direction immediately before the stationary state of the magnification lens.