JP2011076020A - Photographic lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a portable lens capable of automatically switching manual operation and electrical operation by a simple and inexpensive structure, in the portable lens operable manually and electrically. <P>SOLUTION: An operation ring 7 in which operation is performed by both the manual operation and the electrical operation is connected integrally with a lens moving group. During the electrical operation, a traveling wave is controlled by an ultrasonic motor, and thereby the operation ring 7 is driven. Also, during the manual operation, the ultrasonic motor is driven with a standing wave based on detection performed by a pressure-sensitive sensor provided at the rubber knurling tool 8 of the operation ring 7, and thereby control is performed so that the operation ring can be operated by the manual operation. Thereby, switching between the manual operation and the electrical operation can be automatically performed by the simple structure. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a photographing apparatus, and particularly to a photographing lens suitable for a television lens used for television photographing.

  A portable television lens used for television photography can be zoomed manually and manually. During manual operation, the manual ring provided on the lens exterior surface is manually operated to drive the zoom optical system connected to the manual ring. When the motor is electrically driven, the driving force of the DC motor is decelerated by the gear head, and the manual ring is electrically controlled to drive the zoom optical system.

  When switching between manual operation of zoom and electric drive, a method of operating a clutch lever provided in the lens device is general. For example, when switching from electric to manual, the clutch lever is operated to switch the engagement of a part of the gear train disposed between the DC motor and the manual ring from the connected state to the released state (see Patent Document 1).

  On the other hand, recently, a zoom lens that can automatically switch between manual operation and electric operation without switching the clutch lever has also been proposed (see Patent Document 2). This zoom lens is provided with a mechanism for automatically controlling the release and connection of a clutch mechanism disposed between the motor and the manual ring in accordance with the presence or absence of an electric instruction. For a photographer who uses both manual and electric operation methods, there is a great operational merit in that the manual and electric zoom can be switched instantaneously.

JP-A-8-286091 JP 2002-155968 A JP 59-101608 A

  However, the mechanism for automatically controlling the release and connection of the clutch mechanism disposed between the motor and the manual ring in accordance with the presence or absence of an electric instruction has a problem of high cost due to its complicated structure.

  As a means for solving this problem, a method of switching between an electric mode and a manual mode using an ultrasonic motor has been proposed. An example of a mechanism for switching between manual and electric driving without using a complicated clutch mechanism is used, in which the ultrasonic motor is driven by a traveling vibration wave in the electric mode and is driven by a steady traveling wave when the manual mode is set. (See Patent Document 3). However, in this method, when the manual mode is set, the ultrasonic motor is always controlled to drive the steady traveling wave even if the manual operation is not performed. In a portable TV lens with a lot of battery drive, an operation method that requires a large amount of power consumption even when it is not operated is not an optimal means.

  The present invention has been devised to overcome the above problems. An object of the present invention is to provide a portable lens capable of automatically switching between manual and electric switching with a simple and inexpensive structure without causing an increase in power consumption. .

  In order to achieve the above object, a lens apparatus of the present invention has optical means constituting an imaging optical system and an operation ring integrally connected to the optical means, and the operation ring of the operation ring is operated manually and electrically. A manual operation detecting means for detecting manual operation of the operation ring and one or more electric instruction means for instructing to electrically drive the operation ring in a photographic lens that extends the optical means in conjunction with rotation. And a vibration wave motor connected to the operation ring and a control means for controlling the vibration wave motor. When the manual operation detection means detects a manual operation, the control means drives the vibration wave motor to a standing wave. The operation ring is controlled so that it can be operated with a light load, and when the electric instruction is given by the electric instruction means, the vibration wave motor is driven in a traveling wave so as to drive the rotation of the operation ring. .

  Further, the manual operation detecting means compares the output signal of the pressure sensor provided on the operation ring with a predetermined threshold value, and judges the manual operation.

  Furthermore, the pressure sensor is provided integrally with a knurled rubber part.

  Further, the manual operation detecting means is characterized in that a threshold value to be compared with an output signal of the pressure sensor can be adjusted to an arbitrary value.

  Further, the manual operation detecting means is characterized in that it is determined as manual operation when it is detected that the position of the operation ring changes in a state where the electric instruction means does not instruct electric drive.

  Further, the present invention is characterized in that there is selection means for selecting the priority order of the driving method of the vibration wave motor when manual operation and electric instruction are performed simultaneously.

  According to the present invention, it is possible to provide a portable lens excellent in operability that suppresses an increase in power consumption and can automatically switch between manual and electric switching with an inexpensive structure.

Configuration of a photographic lens according to the present invention Illustration of traveling wave and standing wave of ultrasonic motor Explanatory diagram of pressure sensitive sensor output according to the present invention Flowchart of ultrasonic motor control processing according to the present invention Photographic lens configuration diagram of the second embodiment according to the present invention

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  An imaging apparatus showing an example of the present invention will be described in detail with reference to FIGS. FIG. 1 is a structural diagram of a photographic lens used for television photography such as news gathering. In the figure, L is a zoom lens, and a drive unit D storing a control circuit for driving the lens is disposed in the vicinity of the zoom lens L, and the drive unit D is detachably fixed to the zoom lens L. The zoom lens L and the drive unit D are combined to form a photographing lens.

  The basic configuration of the zoom lens and the mechanism of manual and motorized automatic switching, which is a feature of the present invention, will be described with reference to FIG. In the figure, reference numeral 1 denotes a zoom optical system which is held by a lens barrel 2. The lens barrel 2 has at least three roller members 3 projecting from the lens barrel 2, and each roller member 3 rotates about a linear groove 4a provided in the fixed barrel 4 of the zoom lens and the optical axis. The rotating cylinder 5 is engaged with a curved groove 5a. Reference numeral 6 denotes a connecting pin provided on the rotating cylinder 5 and engages with a groove 7a of the operating ring 7 provided on the exterior surface of the taking lens through a groove 4b provided on the fixed cylinder 4 without play.

  In this configuration, when the operating ring 7 is rotated, the rotating cylinder 5 connected by the connecting pin 6 rotates integrally with the operating ring 7. The roller member 3 of the lens barrel 2 moves along the cam lift of the curved groove 5a of the rotating cylinder 5 while being supported by the linear groove 4a of the fixed cylinder 4, and the zoom optical system 1 moves in the optical axis direction. Since the connecting pin 6 that rotates about the optical axis abuts on the end in the circumferential direction of the groove 4b provided in the fixed cylinder 4, the operation ring 7 has an operation end.

  8 is a rubber knurl in which a pressure-sensitive sensor is incorporated. Conductive particles are kneaded into the rubber, and when the rubber is pressed by hand, electricity flows between the conductive particles to determine whether the photographer is touching or not touching the knurl. Can be determined. That is, the rubber knurl 8 has a concave and convex shape that improves the operator's finger contact, and also serves as a touch sensor. The electrode pattern 9 and the brush 10 are fixed inside the rubber knurl 8, and when the operation ring 7 is operated, the brush 10 and the electrode pattern 12 provided on the outer periphery of the pressure adjusting ring 11 serve as a sliding contact. A signal from the provided pressure sensor is transmitted to the drive unit D via the flexible cable 13.

  Next, the structure related to the electric drive of zoom will be described. 14 is a stator that vibrates ultrasonically and is in pressure contact with the rotor 15 that rotates about the optical axis. The stator 14 and the rotor 15 are combined to constitute an ultrasonic motor, and the rotor 15 rotates around the optical axis by applying a traveling wave vibration in the ultrasonic region to the stator 14. 16 is a pressure spring, 17 is a ring-shaped pressure plate that uniformly transmits the force of the spring to the stator, and 11 is a pressure adjusting ring that adjusts the pressure of the pressure spring 16. Reference numeral 19 denotes a motor base that assembles components related to electric drive into this member to form a unit, which is fixed to the fixed barrel 4 of the photographing lens. The pressure adjusting ring 11 is screwed into the motor base 19 to adjust the force for pressing the stator 14 to the rotor 15. A sliding ring 20 that rotates and slides around the motor base 19 is fixed integrally with the rotor 15 via a rubber 21 that absorbs vibration. The side surface of the sliding ring 20 is in contact with a bearing 23 sandwiched between the motor base 19 and the shaft screw 22. Since the sliding ring 20 receives pressure applied to the rotor 15 by the stator 14, the bearing 23 has a role of reducing sliding resistance of the sliding ring 20 in the optical axis direction. Three bearings 23 and shaft screws 22 are provided in the circumferential direction and at equal intervals. The sliding ring 20 is provided with a key groove 20a, and the tip of the shaft screw 24 fixed to the operation ring 7 is engaged with the key groove 20a without backlash. That is, the sliding ring 20 and the manual operation ring 17 rotate integrally through the shaft screw 24, and the rotating cylinder 5 also rotates integrally through the connecting pin 6. In this way, the zoom optical system 1 is driven by applying a traveling wave drive to the stator 14 which is an ultrasonic vibrator during electric drive.

  Next, the configuration of the drive unit D provided near the lens will be described. Reference numeral 30 denotes an electric instruction member for instructing an electric operation of zooming, which is provided on the exterior surface of the drive unit D. The electric instruction member 30 adjusts the zoom speed according to the operation amount of the operation unit. A CPU 31 controls the stator 14 of the ultrasonic motor by using a driver circuit 32 based on a command signal from the electric instruction member 30. That is, the CPU 31 and the driver circuit 32 constitute control means for controlling the ultrasonic motor. The encoder gear 34 meshes with the gear portion 7 b of the operation ring 7, and the zoom position is detected by the encoder 33. The CPU 31 feedback-controls the ultrasonic motor based on the detected zoom position. As shown in the figure, since there is no meshing of gears from the stator 14 which is an electric drive source to the zoom optical system 1, there is no delay in response due to backlash, and electric operation with high responsiveness can be performed. It becomes possible.

  Here, the mechanism of automatic switching between manual and electric which is a feature of the present invention will be described in detail. First, when the photographer operates electrically, the electric instruction member 30 provided in the drive unit is operated. Based on the amount of operation of the electric instruction member 30, the CPU 31 controls the stator 14 to generate ultrasonic waves of traveling waves. The rotor 15 pressurized by the stator 14 receives traveling wave vibration from the stator 14 and rotates around the optical axis. Since the rotor 15 and the rotating cylinder 5 rotate integrally, the zoom optical system 1 is driven.

  Next, the mechanism when the photographer manually zooms will be described. When the photographer grips the rubber knurl 8 provided on the operation ring 7, the CPU 31 determines that the manual operation is performed based on the detection of the pressure sensor embedded in the rubber knurl 8. The CPU 31 instructs the stator 14 to excite standing wave ultrasonic vibration. Here, the difference between the traveling vibration wave and the steady traveling wave of the ultrasonic motor will be described with reference to FIG. Generally, when an ultrasonic motor is driven to rotate, traveling wave vibration is generated in the stator 14. When two vibration waves of phase A and phase B, which are 90 degrees out of phase, are simultaneously applied to the stator 14 as indicated by 2-a in FIG. 2, traveling wave vibration that promotes rotational motion is generated. On the other hand, as shown in 2-b of FIG. 2, when the vibration is applied only to the A phase and the vibration of the other B phase is stopped, the stator 14 generates a standing wave vibration instead of a traveling wave. Rather than encouraging rotational movement, the contact surface between the stator 14 and the rotor 15 simply vibrates. Since the stator 14 and the rotor 15 are in a pressurized state when the stator 14 is not being controlled, the operating force becomes heavy if an attempt is made to manually operate the rotor side. However, when a stationary wave is applied to the stator 14 instead of a traveling wave, the rotor 15 does not rotate, and the rotor 15 side, that is, the operation ring 7 can be manually operated smoothly with a light load. When the photographer releases his hand from the rubber knurl 8, the CPU 31 stops the stationary wave control on the stator 14 based on the signal of the pressure sensor provided in the rubber knurl 8, and the stator 14 and the rotor 15 are in a pressurized state. . Even when manual operation is performed, the ultrasonic motor is controlled, so that power is consumed. However, when manual operation is completed, power is not consumed. Thus, by changing the driving method of vibration generated by the stator 14 manually and electrically, it is possible to automatically switch between manual operation and electric drive with a simple structure without a special switching mechanism. Under photographing conditions where it is necessary to switch between manual operation and electric operation instantaneously, the photographing lens has extremely high operability.

  FIG. 3 shows the relationship between the pressing force of the rubber knurl 8 and the output signal of the pressure-sensitive sensor embedded in the rubber knurl 8. The stronger the photographer grips the rubber knurl, the greater the output signal of the pressure sensor. However, if the photographer does not intend to perform the zoom operation and the rubber knurled 8 is lightly touched by hand for the purpose of supporting the photographing lens, it is wasted power consumption. Therefore, as shown in FIG. 3, a threshold value K for determining manual operation is provided. When the output signal of the pressure sensitive sensor exceeds the threshold value K, the CPU 31 determines that it is a manual operation and performs standing wave control, and when the output signal is K or less, the CPU 31 does not issue a command to the ultrasonic motor. Thereby, unnecessary power consumption of the ultrasonic motor can be suppressed. The threshold value K can be arbitrarily changed according to the photographer's preference using the cross key 35 and the display display 36 provided on the exterior surface of the drive unit D.

  The photographing lens according to the present invention can automatically switch between manual operation and electric operation without any special switching operation, but both manual operation and electric operation can be operated simultaneously. For example, it is possible for the photographer to perform manual operation by setting the photographing lens on a tripod, and at the same time, another operator can remotely perform remote operation using a remote operation member 37 connected to the drive unit D by a cable. In the present invention, a mode changeover switch 38 is provided for determining which is to be prioritized when manual operation and electric operation are performed simultaneously. The control flow of the ultrasonic motor according to the setting of the mode switch 38 will be described with reference to FIG.

  In S101 and S102 in FIG. 4, the CPU 31 monitors the presence / absence of an electric operation and the presence / absence of a manual operation. When an instruction for an electric operation is detected in S103 and a manual operation is not performed in S104, the ultrasonic motor is traveled in S105 to rotate and drive the motor. When not only the electric operation but also the manual operation is detected at S104, the priority set by the mode switch 38 is confirmed at S106. When the mode in which manual operation is prioritized is set, the electric instruction is invalidated in S107, and the ultrasonic motor is driven in a steady wave in S108 to enable manual operation. Conversely, when the mode in which electric operation is prioritized is set in S106, the ultrasonic motor is subjected to traveling wave control in S109, and electric control is performed against manual operation. Further, in S110, the display unit 36 displays a warning for the manual operator that the electric operation is prioritized. The above is the control flow of the ultrasonic motor when the manual operation and the electric operation are simultaneously performed. When there is no electric zoom instruction in S103 and no manual operation is performed in S111, the stop state is maintained without issuing a control signal to the ultrasonic motor as shown in S112. When only manual operation is detected in S111, the ultrasonic motor is controlled in steady wave in S113 so that manual operation is possible.

  As described above, the control method of the ultrasonic motor is changed by detecting the presence or absence of manual operation and electric operation of the taking lens, and discriminating between three operation situations: manual operation, electric operation, and no lens operation. By doing so, it is possible to automatically switch between manual and electric switching with a simple and inexpensive structure. In addition, by using an annular ultrasonic motor, it is possible to provide a photographing lens with high operability and high responsiveness by reducing backlash of a power transmission system during electric driving. Furthermore, in this embodiment, since the operation ring has an operation end and cannot be rotated except within a predetermined angle range, it is also characterized in that it has operability preferred by professional users who handle broadcasting equipment.

  In this embodiment, a pressure sensor is exemplified as means for detecting manual operation. However, for example, it is possible to use a touch sensor that detects a change in capacitance when touched by a human hand. Further, instead of using a touch sensor, the CPU 31 can determine that the operation is manual operation when the encoder 33 detects that the position of the operation ring 7 changes in a state where the electric instruction member 30 does not instruct electric driving. The means for detecting the manual operation may be any method.

  In the present embodiment, an annular ultrasonic motor centered on the optical axis has been exemplified. However, a small-diameter ultrasonic motor may be provided in the drive unit D to drive the operation ring 7. The use of a small-diameter ultrasonic motor can be expected to reduce the size of the taking lens.

  Further, the zoom of the taking lens is described as an example, but the present invention can be applied to focus, iris or macro.

  A photographic lens according to a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the feature of the present invention that switches between manual and electric by changing the driving method of the ultrasonic motor is applied to improving the operability of the autofocus lens. The autofocus lens of the present embodiment employs a contrast detection method that performs focus detection using a video signal obtained by an image sensor. In this method, also called a hill-climbing method, a part of the focusing optical system is finely reciprocated (wobbled) to extract a high frequency component from the video signal of the image sensor at a predetermined sampling interval. This is a method for determining that the in-focus state is when the level value of the high-frequency component reaches a peak.

  The configuration diagram shown in FIG. 5 is similar to FIG. 1 described in the first embodiment. In the embodiment of FIG. 1, the zoom optical system is driven using an ultrasonic motor, but in FIG. 5, the focus optical system is driven by an ultrasonic motor. Although the optical system to be driven is different, the second embodiment can be described with the same system configuration as in FIG. In FIG. 5, the parts having the same symbols as those in FIG. 1 play the same role, so that the detailed description is omitted and only the differences from the first embodiment will be described.

  In FIG. 5, 41 is a focus optical system that moves in the optical axis direction for focus adjustment, and 42 is a zoom optical system. Reference numeral 43 denotes a wobbling optical system for determining the focus state, and the motor 44 reciprocates at high speed. A relay optical system 45 condenses the light transmitted through the zoom lens onto the camera device C. A camera device C to which the zoom lens L is attached via a mount component (not shown) has a CCD 46 that converts subject light into an electrical signal and a video processing circuit 47 that generates a video signal. When autofocusing is performed, the drive unit D captures a video signal captured by the camera device C. The CPU 31 controls the focus optical system 41 by driving the stator 14 so that the level value of the high frequency component of the video signal becomes a peak. In this embodiment, auto-focusing is realized by controlling two optical systems, a wobbling optical system 43 that detects the in-focus state and a focusing optical system 41 that focuses. In general, the focus operation of a broadcasting photographing lens is performed by operating an operation ring 7 having an operation end as shown in FIG. Since the photographer grasps the position of the lens by the amount of operation from the operation end, it is significant to have the operation end for manual operation. In such a broadcast zoom lens, the focus optical system is generally positioned closer to the subject side than the zoom optical system. Since it is difficult to wobbling a large-diameter and heavy optical system at high speed, the focus optical system 41 is controlled when focusing. On the other hand, the wobbling optical system 43 having a small diameter and a light mass is controlled at high speed in order to detect the in-focus state. Thus, the two optical systems have different roles.

  Next, a mechanism for automatically switching between manual focusing and electric focusing will be described. Reference numeral 51 denotes a switch for instructing autofocus. In this embodiment, the autofocus function is operated while the switch is kept pressed. Specifically, the CPU 31 controls the motor 44 so that the wobbling optical system 43 is reciprocated minutely. Then, the presence / absence of focusing and the direction to be focused are determined from the contrast of the video signal obtained from the video processing circuit 47. When not in focus, the CPU 31 applies a traveling wave vibration to the stator 14 to drive the focus optical system 41 and controls the focus optical system 41 until it is determined to be in focus by the video signal.

  However, the autofocus method that uses the video signal obtained by the CCD to detect the focus may not be able to focus accurately if the subject's contrast is not clear. Therefore, it is desirable to have a photographic lens that can be manually operated instantly with priority given to the photographer's intention after the end of autofocus or during autofocus.

  In order to give priority to the manual operation over the autofocus operation, the mode changeover switch 38 is set to the manual priority mode as in the first embodiment. In this embodiment, when the rubber knurl 8 provided on the operation ring 7 is operated after the autofocus is finished or during the autofocus, the pressure sensor in the rubber knurl 8 detects the manual operation. As in the first embodiment, the CPU 31 excites standing wave vibration in the stator 14 to change the operation ring 7 so that it can be manually operated, and the photographer manually adjusts the focus optical system 41. Since the operation ring 7 and the focus optical system 41 are mechanically connected, it is possible to quickly focus and correct.

  The focus optical system 41 can be operated not only using the switch 51 for instructing autofocus but also using a focus demand 52 which is an external operation device for instructing focusing from a remote location via a cable. The control flow when the manual operation and the electric drive are operated simultaneously is the same as that shown in FIG. 4 described in the first embodiment.

  In this way, manual operation and electric drive can be automatically switched without a special switching mechanism by changing the drive method of vibration generated by the stator 14 of the ultrasonic motor between the two operation methods of manual operation and electric drive. . As exemplified in the present embodiment, it is possible to quickly correct the focus manually after the autofocus necessary for the autofocus lens with a simple configuration.

L Zoom lens D Drive unit 7 Operation ring 8 Rubber knurl 14 Stator 15 Rotor

Claims (6)

  In a photographing lens having an optical means constituting an imaging optical system and an operation ring integrally connected to the optical means, and extending the optical means in conjunction with rotation of the operation ring during manual and electric operation, Manual operation detecting means for detecting manual operation of the operation ring, one or more electric instruction means for instructing to electrically drive the operation ring, a vibration wave motor connected to the operation ring, and the vibration Control means for controlling the wave motor, and when the manual operation detecting means detects a manual operation, the control means drives the vibration wave motor to a standing wave so that the operation ring can be operated with a light load. And a traveling wave drive of the vibration wave motor so as to rotationally drive the operation ring when the electric instruction is given by the electric instruction means.   2. The photographing lens according to claim 1, wherein the manual operation detecting means compares the output signal of a pressure sensitive sensor provided on the operation ring with a predetermined threshold value to determine manual operation.   The photographing lens according to claim 2, wherein the pressure-sensitive sensor is provided integrally with a knurled rubber part.   4. The photographing lens according to claim 2, wherein the manual operation detecting means can adjust a threshold value to be compared with an output signal of the pressure sensor to an arbitrary value.   The photographing lens according to claim 1, wherein the manual operation detection unit determines that the manual operation is performed when it detects that the position of the operation ring changes in a state where the electric instruction unit does not instruct electric drive.   6. The photographing lens according to claim 1, further comprising selection means for selecting a priority order of driving methods of the vibration wave motor when a manual operation and an electric instruction are performed simultaneously.

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