JP3799590B2 - Conversion lens switching device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a conversion lens switching device, and more particularly to a conversion lens switching device used in a broadcast television camera or the like for selectively inserting / removing two conversion lenses having different magnifications into / from a photographing optical path.
[0002]
[Prior art]
In recent years, in the field of broadcast television cameras and the like, cameras that can selectively switch between an aspect ratio of 4: 3 and an aspect ratio of 16: 9 have been put into practical use. In this type of switchable camera, for example, when a 16: 9 CCD element is used on the imaging surface and the aspect ratio is set to 4: 3, the left and right partial areas of the CCD element are not used. Only the area with an aspect ratio of 4: 3 in the center is used. Therefore, when the aspect ratio is set to 4: 3, the angle of view is narrowed by about 20%, and there is a problem that the image captured on the screen does not satisfy the original specifications of the photographing lens.
[0003]
In order to solve this problem, a method is known in which the image size φ is changed by inserting / removing a conversion lens (ratio converter) of about 0.8 times on the photographing optical path to eliminate the above-mentioned drawbacks. A mechanism for inserting and removing the two conversion lenses on the optical axis in this way is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-171043.
In this publication, two conversion lenses having different magnifications are rotatably supported, and each lens can be moved from a retracted position outside the photographing optical path to a use position in the photographing optical path. Then, two operation levers are provided on the front and rear surfaces of the lens device casing as operation members for individually rotating each lens.
[0004]
[Problems to be solved by the invention]
However, in the conventional conversion lens switching mechanism, when the extender insertion lever is operated by operating the ratio converter switching lever and operating the extender switching lever with the ratio converter inserted in the use position, The ratio converter is pushed out of the use position and moved to the retracted position. However, after that, even if the extender switching lever is operated to remove the extender from the photographing optical path, the ratio converter remains in the retracted position. Therefore, in order to return the ratio converter to the use position, the ratio converter switching lever must be operated again, and there is a drawback that the switching operation is complicated.
[0005]
On the other hand, in order to deal with such a problem, Japanese Patent Application Laid-Open No. 8-184889 discloses that an extender lens and a shrinker (corresponding to a ratio converter) are connected via a clutch, and the operation of switching between the extender lens and the shrinker is performed with one operation of the operation member. To do at the same time. However, the configuration using the clutch as described in the publication has a problem that the switching mechanism is complicated.
[0006]
The present invention has been made in view of such circumstances, and by using a simple mechanism, any one of two conversion lenses having different magnifications can be selectively inserted and removed. To provide a conversion lens switching device capable of making the insertion / removal operation of the one (in use) conversion lens follow the insertion / removal operation of the other conversion lens (extender) when the (ratio converter) is used. Objective.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a conversion lens switching device for inserting / removing two types of conversion lenses having different magnifications into / from a photographing optical path according to a selection operation, and a first retraction position and a photographing optical path outside the photographing optical path. A first conversion lens which is provided so as to be rotatable between the first use positions therein, and an operation for moving the first conversion lens to the first retracted position or the first use position. The first operating means is provided so as to be rotatable between a second retracted position outside the photographing optical path and a second use position in the photographing optical path, and the first conversion lens is directed to the first use position. And the second conversion lens arranged so that the frame portion of the first conversion lens comes into contact with the second conversion lens and the second conversion lens at the second retracted position or the second use position. A second operation means for performing an operation for movement; the second operation means; An interlocking member that rotates in conjunction with the rotational movement of the conversion lens; and an urging unit that connects the interlocking member and the second operating means to urge the interlocking member in the rotational direction. And an urging means arranged so that the urging direction is reversed according to the operation direction of the two operation members.
[0008]
According to the present invention, when the first and second conversion lenses are both retracted from the photographing optical path (through state), the first conversion lens is moved out of the photographing optical path by operating the first operating means. It is possible to move freely between the first retracted position and the first use position in the photographing optical path, and only the first conversion lens can be inserted and removed independently.
Similarly, in this through state, by operating the second operating means, the second conversion lens can be freely moved between the second retracted position and the second use position. Only the conversion lens can be inserted and removed independently.
[0009]
On the other hand, when the second conversion lens is inserted in the second use position in the photographing optical path, the first operation lens is operated to advance the first conversion lens into the photographing optical path. The frame portion of the conversion lens comes into contact with the second conversion lens, and the second conversion lens is pushed out from the photographing optical path by the rotation of the first conversion lens. Thus, the second conversion lens moves to the second retracted position, and instead the first conversion lens moves to the first use position in the photographing optical path.
[0010]
At this time, the second conversion lens opposes the urging force of the urging means provided between the connecting member and the second operation means, and the operation position of the second operation member (second conversion lens). Is moved forcibly in the opposite direction (the direction in which the second conversion lens retracts). Accordingly, when the first operating means is operated to move the first conversion lens in the direction of retracting from the photographing optical path, the force stored in the urging means is released, and the second force is applied by the urging force. The conversion lens returns to the second use position in the photographing optical path.
[0011]
Thereby, when the second conversion lens is used, the insertion / removal operation of the second conversion lens can be made to follow the insertion / removal operation of the first conversion lens, and the switching operation is facilitated. Further, the second conversion lens forcedly pushed out of the photographing optical path by the insertion of the first conversion lens is positioned in the original photographing optical path by the urging force of the urging means together with the retracting operation of the first conversion lens ( Since it is returned to the first use position), a clutch or the like is not required and a simple configuration can be achieved.
[0012]
In particular, further space saving can be achieved by providing the first conversion lens and the second conversion lens so as to be rotatable independently of each other on a common axis.
INDUSTRIAL APPLICABILITY The present invention can be applied to a conversion lens switching device that selectively switches between an enlargement system lens (extender) of 2 times or more and a reduction system lens (ratio converter) of less than 1 × (1 ×). It is more effective when incorporated in a television lens used in a television camera that can selectively switch the aspect ratio of the imaging screen between 4: 3 and 16: 9.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a conversion lens switching device according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an external plan view of a zoom lens device (ENG lens) for a television camera to which a conversion lens switching device according to an embodiment of the present invention is applied. A TV camera zoom lens device 1 shown in FIG. 1 is an inner focus zoom lens used in a broadcast TV camera such as an ENG camera. A lens hood 4 is provided on the front surface of the lens body 2, and A drive unit 6 is attached to the side.
[0014]
The lens body 2 has a focus gear 8, a zoom gear 10 and an iris gear 12 formed on the peripheral surface of the lens body 2, and each of the gears 8, 10, 12 is a corresponding power transmission system gear ( (Not shown). In FIG. 1, reference numeral 14 is a focus ring, 16 is a zoom ring, 17 is a zoom seesaw control lever, 18 is a VTR switch, and 19 is a strap band.
[0015]
The internal structure of the lens body 2 is not shown, but as is well known, in the lens barrel, in order from the front, a fixed focus lens group, a moving focus lens group, a variable power lens system, a correction lens system, an iris, In addition, an extender unit 20 corresponding to a conversion lens switching device is provided behind the relay lens.
An extender switching lever (first operation means) 22 is provided on the rear end surface of the extender portion 20 (see FIG. 2), and a ratio converter switching lever is provided on the front end surface of the extender portion 20 as shown in FIG. (Second operation means) 24 is provided. In FIG. 3, the lens hood 4 is omitted.
[0016]
4 is a front perspective view of the extender portion 20, and FIG. 5 is a cross-sectional view thereof. The extender unit 20 includes a case body 26. In the case body 26, for example, a double extender (corresponding to the first conversion lens) 28 and a ratio converter (second conversion) of about 0.8 times are provided. 30 (corresponding to a lens). The extender 28 and the ratio converter 30 are each composed of one or a plurality of lenses.
[0017]
The frame 32 of the extender 28 has a holding ring 32A for attachment to the support shaft 34 (see FIG. 5), and the extender 28 is rotatably supported by the support shaft 34 via the ring 32A.
Similarly, the frame body 36 of the ratio converter 30 has a holding ring 36A for attachment to the support shaft 34, and the ratio converter 30 is rotatably supported by the support shaft 34 via the ring 36A.
[0018]
The position P1 shown in FIG. 4 is the retracted position (first retracted position) of the extender 28, and the position P2 is the retracted position (second retracted position) of the ratio converter 30. The position Q becomes the use position in the photographing optical path.
The case body 26 is provided with a stopper (not shown) for locking the extender 28 at the retracted position P1, and the edge of the frame body 32 of the extender 28 comes into contact with the stopper so that the extender 28 is It is positioned at a predetermined retracted position (P1).
[0019]
Similarly, a stopper (not shown) is provided on the case body 26 to lock the ratio converter 30 at the retracted position P2, and the edge of the frame 36 of the ratio converter 30 abuts on the stopper. The ratio converter 30 is positioned at a predetermined retracted position (P2).
Further, a mounting portion 32B having a screw threaded portion is formed on the frame body 32 of the extender 28, and a stopper 38 is mounted on the mounting portion 32B. On the other hand, the frame 36 of the ratio converter 30 is formed with a flat portion (contact portion) 36B with which the head of the stopper 38 abuts. The extender 28 and the ratio converter 30 are positioned at a predetermined use position Q by the stopper 38 of the extender 28 being brought into contact with the flat portion 36B of the ratio converter 30 and being locked.
[0020]
The case body 26 is provided with a stopper (not shown) for positioning the extender 28 and the ratio converter 30 through a screw threaded portion, and the extender 28 and the ratio converter 30 are adjusted by adjusting the screwing amount of the stopper. The locking position can be adjusted.
As shown in FIG. 5, the holding rings 32 </ b> A of the extender 30 and the holding rings 36 </ b> A of the ratio converter 30 are alternately arranged on the support shaft 34. Further, gears 40 and 42 are integrally formed on the holding rings 32A and 36A.
[0021]
A shaft 44 of the extender switching lever 22 is rotatably supported by the case body 26, and a gear 45 is integrally fixed to an end portion of the shaft 44. The gear 45 is engaged with the gear 40 of the holding ring 32 </ b> A and is engaged with the gear 46. The gear 46 is rotatably supported by a shaft 48 fixed to the case body 26, and a pin 50 is implanted in the gear 46.
[0022]
Further, a pin 52 is fixed at a predetermined position of the case body 26, and a tension spring 54 is passed between the pins 50 and 52. In other words, one end of the tension spring 54 is engaged with a pin 52 that is fixedly fixed, and the other end is engaged with a pin 50 that rotates together with the gear 46. Thus, although the gear 46 is urged in the circumferential direction by the tension spring 54, the fulcrum position of the tension spring 54 is moved depending on the rotation position of the gear 46, and the urging direction is changed. With this configuration, the extender 28 can be rotated around the support shaft 34 via the gears 45 and 40 by rotating the extender switching lever 22.
[0023]
A shaft 58 of the ratio converter switching lever 24 is rotatably supported by the case body 26, and a plate member 60 is integrally provided at the end of the shaft 58. A pin 62 is implanted in the plate member 60.
On the other hand, a fan-shaped gear (an interlocking member) 64 is meshed with the gear 42 formed on the holding ring 36 </ b> A of the ratio converter 30. The fan-shaped gear 64 is rotatably supported by a shaft 68 fixed to the plate member 66, and the plate member 66 is attached to the case body 26 by bolts 70.
[0024]
A pin 72 is implanted in the fan-shaped gear 64, and a tension spring (biasing means) 74 is passed between the pin 72 and the pin 62 of the plate member 60. That is, one end of the tension spring 74 is engaged with the pin 72 of the sector gear 64, and the other end is engaged with the pin 62 that rotates integrally with the ratio converter switching lever 24. In this way, the fan-shaped gear 64 is urged in the rotation direction by the tension spring 74, but the fulcrum position of the tension spring 74 is moved by the operation position of the ratio converter switching lever 24 and the rotation position of the fan-shaped gear 64. The biasing direction is changed.
[0025]
Thus, by rotating the ratio converter switching lever 24, the rotating operation is transmitted to the fan-shaped gear 64 via the tension spring 74, and the ratio converter 30 is moved to the support shaft 34 via the fan-shaped gear 64. It can be rotated around.
Next, the operation of the zoom lens device for a television camera provided with the conversion lens switching device configured as described above will be described.
[0026]
First, the operation of the extender 28 alone will be described. As shown in FIG. 6, when the extender 28 is in the retracted position P1, the gear 46 is urged clockwise by a tension spring 54 in the drawing. Accordingly, a counterclockwise force is applied to the gear 45 that meshes with the gear 46, and a clockwise force is applied to the frame 32 of the extender 28 that meshes with the gear 45. Thus, the extender 28 is pressed against a stopper (not shown) and maintained at the retracted position P1.
[0027]
When the extender switching lever 22 is operated in the clockwise direction in FIG. 6 from this state, as shown in FIG. 7, the gear 45 fixed to the shaft 44 of the extender switching lever 22 rotates in the clockwise direction. By this operation, the frame 32 of the extender 28 that meshes with the gear 45 is rotated counterclockwise about the shaft 34, and the extender 28 moves to the use position Q.
[0028]
Further, the gear 46 that meshes with the gear 45 also rotates counterclockwise. The position of the pin 50 is moved by the rotation of the gear 46, and the urging direction of the gear 46 by the tension spring 54 is changed. That is, the gear 46 is urged counterclockwise in FIG. 7, and a force is applied to the frame 32 of the extender 28 in the counterclockwise direction. Thus, the stopper 38 of the extender 28 is pressed against the flat portion 36B of the frame 36 of the ratio converter 30, and the extender 28 is maintained at the use position Q.
[0029]
The extender switching lever 22 can be operated counterclockwise from the state shown in FIG. 7 to return to the retracted state shown in FIG.
Next, the operation of the ratio converter will be described.
When a TV camera (switchable camera) capable of switching the aspect ratio to 4: 3 or 16: 9 is used at an aspect ratio of 16: 9, the effective pixel area (for example, image size φ11) of 16: 9 is used as it is. Will be used. In this case, as shown in FIG. 8, the extender 28 and the ratio converter 30 are both set to the retreat positions P1 and P2 (through state).
[0030]
As shown in FIG. 8, when the ratio converter switching lever 24 is set to the ratio converter out position and the ratio converter 30 is in the retracted position P2, the sector gear 64 is rotated clockwise in FIG. It is energized. Accordingly, a counterclockwise force is applied to the frame 36 of the ratio converter 30 that meshes with the fan-shaped gear 64, and the ratio converter 30 is pressed against a stopper (not shown) and maintained at the retracted position P2.
[0031]
On the other hand, when the aspect ratio is 4: 3, only the 4: 3 area (image size φ9) is used in the 16: 9 effective pixel area. In such a case, a ratio converter 30 for widening the angle of view and obtaining the same image size as that of the image size φ11 is inserted into the photographing optical path.
That is, as shown in FIG. 9, the ratio converter switching lever 24 is operated 180 degrees clockwise to set the ratio converter in position where the ratio converter 30 is positioned at the use position Q. When the ratio converter switching lever 24 is operated in the clockwise direction, the plate member 60 fixed to the shaft 58 of the ratio converter switching lever 24 rotates in the clockwise direction, and the pin 62 supporting one end of the tension spring 74 is rotated. The position moves.
[0032]
In this way, the fulcrum of the tension spring 74 moves, and the urging direction of the sector gear 64 by the tension spring 74 changes. That is, the sector gear 64 is urged counterclockwise, and the sector gear 64 is rotated counterclockwise by the urging force of the tension spring 74. With the rotation of the fan-shaped gear 64, the frame 36 of the ratio converter 30 rotates clockwise about the shaft 34, and the ratio converter 30 moves to the use position Q. Then, the flat portion 36B of the ratio converter 30 is pressed against the head of the stopper 38 of the extender 28, and the ratio converter 30 is maintained at the use position Q.
[0033]
When the extender insertion lever 22 is operated by operating the extender switching lever 22 in the state shown in FIG. 9 (extender out, ratio converter in), the extender 28 rotates in the direction of the use position Q as described in FIG. Move. At this time, since the stopper 38 of the extender 28 and the flat portion 36B of the ratio converter 30 are in contact with each other, the ratio converter 30 is pushed out of the photographing optical path from the use position Q by the insertion operation of the extender 28 (see FIG. 10). ).
[0034]
The ratio converter 30 is forcibly moved in the direction opposite to the operation position of the ratio converter switching lever 24 (the ratio converter-in setting position) (the retracted position P2 corresponding to the ratio converter-out) to form a fan shape. The gear 64 rotates in the clockwise direction in FIG. 10 against the urging force of the tension spring 74.
As a result, the pin 72 that supports one end of the tension spring 74 moves and the tension spring 74 is stretched, and a force in the direction in which the spring contracts is stored in the tension spring 74. Thus, the ratio converter 30 moves to the retracted position P2, and instead, the extender advances to the use position Q in the photographing optical path.
[0035]
Next, when the extender switching lever 22 is operated to set the extender out in the state shown in FIG. 10, the extender 28 is retracted from the photographing optical path in accordance with the operation (see FIG. 11). Then, when the extender 28 moves from the use position Q to the retracted position P1, the fan-shaped gear 64 is rotated clockwise as shown in FIG. 11 by the force stored in the tension spring 74. Thus, the ratio converter 30 returns to the use position Q in the photographing optical path.
[0036]
Thereby, when the ratio converter 30 is used, the insertion / removal operation of the ratio converter 30 can be made to follow the insertion / removal operation of the extender 28, and the lens switching operation is facilitated. Further, since the ratio converter 30 forcedly pushed out from the use position Q by the insertion of the extender 28 is returned to the original use position Q by the urging force of the tension spring 74 together with the retracting operation of the extender 28, a clutch or the like No complicated mechanism is required.
[0037]
Note that the ratio converter switching lever 24 can be operated counterclockwise from the state shown in FIG. 9 to return to the retracted state shown in FIG.
FIG. 12 shows a state in which the extender 28 is moved to the use position Q by operating the extender switching lever 22 from the state shown in FIG. 8 (through state). When using a switchable camera with an aspect ratio of 16: 9, or when using a standard camera with an aspect ratio of 4: 3, the state shown in FIG. 8 (through state) is usually set. When the extender 28 is used, the extender switching lever 22 is rotated as described with reference to FIG. 7 to match the extender-in setting position. By this operation, the extender 28 moves to the use position Q as shown in FIG.
[0038]
Further, when the use of the extender 28 is released, the extender switching lever 22 is rotated in the reverse direction to match the extender-out setting position. By this operation, the extender 28 moves to the retracted position P1 as shown in FIG. 8, and returns to the through state.
In the above embodiment, the case of switching between the double extender 28 and the ratio converter 30 of about 0.8 has been described as an example, but the magnification of the conversion lens can be various magnifications.
[0039]
In the above embodiment, the case where the present invention is applied to a zoom lens device for a television camera has been described as an example. However, the present invention can be widely applied to various photographing optical systems.
[0040]
【The invention's effect】
As described above, according to the conversion lens switching device of the present invention, the first operation means for inserting / removing the first conversion lens, and the second operation means for inserting / removing the second conversion lens; By providing, each conversion lens can be switched individually. In particular, the interlocking member that rotates in conjunction with the rotational operation of the second conversion lens and the second operating means are connected by the biasing means, and the interlocking member is attached in the rotational direction by the biasing means. Since the biasing direction is changed in accordance with the operation direction of the second operation member, the second conversion lens forcedly pushed out of the photographing optical path by the insertion of the first conversion lens, The first conversion lens can be returned to the original use position (first use position) in the imaging optical path by the urging force of the urging means together with the retracting operation of the first conversion lens.
[0041]
In this way, when the second conversion lens is used, the insertion / removal operation of the second conversion lens can be made to follow the insertion / removal operation of the first conversion lens, and the lens switching operation is facilitated. In addition, there is an advantage that a conventional clutch mechanism or the like is unnecessary and can be easily configured.
Furthermore, further space saving can be achieved by providing the first conversion lens and the second conversion lens so that they can rotate independently on a common axis.
[0042]
INDUSTRIAL APPLICABILITY The present invention can be applied to a conversion lens switching device that selectively switches between an enlargement system lens (extender) of 2 times or more and a reduction system lens (ratio converter) of less than 1 × (1 ×). It is more effective when incorporated in a television lens used in a television camera that can selectively switch the aspect ratio of the imaging screen between 4: 3 and 16: 9.
[Brief description of the drawings]
1 is an external plan view of a zoom lens device for a television camera to which a conversion lens switching device according to an embodiment of the present invention is applied. FIG. 2 is a rear view of the zoom lens device for a television camera shown in FIG. 1 is a front view of the zoom lens device for a TV camera shown in FIG. 1. FIG. 4 is a front perspective view of the extender portion shown in FIG. 1. FIG. 5 is a sectional view of the extender portion. FIG. 7 is a front perspective view of the main part used for explaining the operation of the extender. FIG. 8 is for explaining the operation of the conversion lens switching device according to the embodiment of the invention. Fig. 9 is a front perspective view of the main part used. Fig. 9 is a front perspective view of the main part used for explaining the operation of the conversion lens switching device according to the embodiment of the invention. Fig. 10 is a conversion according to the embodiment of the invention. Explain the action of the lens switching device FIG. 11 is a front perspective view of the main part used for explaining the operation of the conversion lens switching device according to the embodiment of the present invention. FIG. 12 is an embodiment of the present invention. Front perspective view used to explain the operation of the conversion lens switching device according to
DESCRIPTION OF SYMBOLS 1 ... Zoom lens apparatus 2 for TV cameras ... Lens body 6 ... Drive unit 20 ... Extender part (conversion lens switching device)
22 ... Extender switching lever (first operating means)
24. Ratio converter switching lever (second operating means)
28 ... Extender (first conversion lens)
30 ... Ratio converter (second conversion lens)
32 ... Extender frame 34 ... Support shaft 36 ... Ratio converter frame 42 ... Gear 64 ... Fan-shaped gear (interlocking member)
74 ... Tension spring (biasing means)

Claims (5)

In a conversion lens switching device that inserts / removes two types of conversion lenses having different magnifications into / from the photographing optical path according to a selection operation
A first conversion lens provided so as to be rotatable between a first retracted position outside the photographing optical path and a first use position in the photographing optical path;
First operating means for performing an operation for moving the first conversion lens to the first retracted position or the first use position;
When the first conversion lens is moved in the direction toward the first use position, it is provided so as to be rotatable between a second retracted position outside the photographing optical path and a second use position in the photographing optical path. A second conversion lens arranged so that the frame portion of the first conversion lens contacts;
Second operating means for performing an operation for moving the second conversion lens to the second retracted position or the second use position;
An interlocking member that rotates in conjunction with the rotational operation of the second conversion lens;
An urging unit that couples the interlocking member and the second operation unit and urges the interlocking member in a rotation direction so that the urging direction is reversed according to the operation direction of the second operation member. A biasing means disposed on
A conversion lens switching device comprising: 2. The conversion lens switching device according to claim 1, wherein the first conversion lens and the second conversion lens are rotatably supported on a common axis. The interlocking member is connected to the second conversion lens via a gear,
The one end of a tension spring corresponding to the biasing means is fixed to the connecting member, and the other end of the tension spring is fixed to the second operation member. Conversion lens switching device. 2. The conversion lens switching device according to claim 1, wherein a magnification system lens of 2 times or more is provided as the first conversion lens, and a reduction system lens of less than 1 × magnification is provided as the second conversion lens. . 2. The conversion lens switching device according to claim 1, wherein the conversion lens switching device is applied to a television lens applicable to a television camera capable of selectively switching an aspect ratio of an effective imaging screen between 4: 3 and 16: 9.

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