JP2006064941A - Television lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce influence by the inertia of a counter weight in the case of selecting a servo operation system in a television lens. <P>SOLUTION: The television lens is equipped with a clutch selecting either a uniaxial two-operation system or a servo operation system, and the counter weight preventing the positional change of an optical system caused by attitude change, and arranged on a motive power transmitting member side by the uniaxial two-operation system of the clutch. Thus, the counter weight is separated by the clutch selecting the operation system. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a television lens, and more particularly to a television lens that can select either a single-axis two-operation method or a servo operation method for a zoom operation.

Japanese Patent Application Laid-Open No. 2003-26883 discloses a mechanism that applies torque to a zoom cam in a direction that cancels the internal weight of the internal optical system in order to prevent a change in the zoom position due to the internal weight of the internal optical system when the posture is tilted. And Patent Document 2 and the like. (Hereafter referred to as counterweight)
On the other hand, in the case of a servo-operated television lens, there is no need for counterweight because the servo drive system holds the weight of the internal optical system.

Further, in a television lens that can select either a single-axis two-operation method or a servo-operation method for a zoom operation, a counterweight is required when the single-axis two-operation method is selected.
Japanese Patent Laid-Open No. 50-160036 JP 52-34725 A JP 2000-333070 A

  However, in a TV lens that can select either the 1-axis 2-operation system or the servo operation system, the inertia of the counterweight is affected when the servo operation system is selected, so a large motor driving force is required and the power consumption is large. Become.

  Or, if the same power consumption is used, there is a problem that the servo speed becomes slow.

  Therefore, as a method of avoiding this, a method of separating the counterweight at the time of servo is conceivable, and Patent Document 3 is proposed as a similar structure.

This is a proposal for correcting the front / rear balance of the lens barrel, but the balancer cam can be used as a counterweight so as to cancel the zoom cam torque caused by the weight of the optical system. However, when this method is used, a new clutch is required to separate the counterweight. The structure is complicated and the entire lens becomes large and heavy. The power consumption increases.

  In order to solve the above problems, the first and second inventions related to the present application are a clutch capable of selecting either a single-axis two-operation method or a servo operation method, and prevents a change in the position of the optical system due to a change in posture. The counterweight can be separated by the clutch that selects the operation method by arranging the counterweight on the side of the power transmission member by the one-axis two-operation method of the clutch.

  According to a third aspect of the present application, the backlash of the operation unit is reduced by inputting the operation force of the 1-axis 2-operation system and the output of the counterweight in parallel to the power transmission member side of the 1-axis 2-operation system of the clutch. Reduced.

As explained above, it is possible to select either a 1-axis 2-operation system or a servo-operation system, a counterweight that prevents a change in the position of the optical system due to an attitude change, and a 1-axis 2-operation system of the clutch. By arranging the counterweight on the power transmission member side, the counterweight can be separated by the clutch that selects the operation method. The configuration can be simplified and the lens can be made smaller and lighter.

  2. Power consumption can be reduced.

3. It can be produced at low cost.
There are effects such as.

  FIG. 1 is a drawing that best represents the features of the present invention. 1 is a lens barrel, 2 is a focus optical system, 3 is a variator optical system, and is guided straight in the direction of the optical axis by the lens barrel 1. The member 8 is engaged. A compensator optical system 3 is guided linearly in the optical axis direction by the lens barrel 1, and is engaged with the zoom cam 7 by a guide member 71.

  Reference numeral 5 denotes an extender optical system. A plurality of extender optical systems are arranged on the turret 6 so that an arbitrary magnification can be selected. A zoom cam 7 is provided with cam grooves for a variator and a compensator on a cylindrical surface and is engaged with guide members 8 and 7, respectively. By rotating the cam, the variator optical system 3 and the compensator optical system 4 can be used as desired. Arrange in positional relationship. Reference numeral 11 denotes a clutch for switching the driving force of the zoom cam. Reference numeral 9 denotes a push-pull pulley for inputting power for one-axis two operation. Reference numeral 10 denotes a servo pulley for inputting power for servo operation. Reference numeral 70 denotes an actuator that operates the clutch, and reference numeral 12 denotes a zoom motor that drives the zoom cam by a servo operation. The zoom motor is driven by an operation demand (not shown) and a command from the control circuit.

  A belt 13 transmits the driving force of the zoom motor to the servo pulley 10. Reference numeral 14 denotes an operation rod which is an operation portion for one-axis two-operation, and is linearly guided by a sliding tube 15. Reference numeral 16 denotes a wire for connecting the operating rod 14 and the counterweight outer cylinder 17, and converts the linear motion of the operating rod 14 into the rotational motion of the outer cylinder 17. A pulley is provided at the tip of the outer cylinder 17, and the rotational force is transmitted to the pushing / pulling pulley 9 by the belt 18. Reference numeral 19 denotes a rotating shaft of the outer cylinder 17, which also serves as a straight guide for the counterweight 20. Reference numeral 20 denotes a counterweight. The engagement member 21 is engaged with a linear groove provided on the shaft 19 so as to be able to advance straight, and is held so as to be able to go straight when rotation about the axis of the shaft 19 is restricted. Further, a cam groove is provided on the outer diameter, and an engagement member 22 fixed to the outer cylinder 17 is slidably engaged.

  Here, the function of the counterweight will be described. When the attitude of the lens is tilted, the variator optical system 3 and the compensator 4 are guided in a straight line by the lens barrel 1, and a moving force is generated in the optical axis direction due to the tilt of the attitude. The force is converted into rotational torque of the zoom cam 7 by a cam provided on the outer diameter of the zoom cam 7.

  On the other hand, when the posture of the lens is tilted, the counterweight 20 also generates a moving force in the axial direction of the tilt shaft 19. The force is converted into a rotational force around the shaft 19 by the engaging member 22 engaged by a cam provided on the outer diameter, and a rotational torque is generated in the outer cylinder 17. Therefore, by determining the cam shape provided on the outer diameter of the counterweight so as to strike against the torque generated in the zoom cam described above, zoom (self-weight zoom) generated by tilting the lens and self-axis 2 It is possible to suppress a change in zoom operation force during operation.

  Reference numeral 23 denotes a selection unit that selects either the one-axis two-operation method or the servo operation method, and reference numeral 24 denotes a control circuit that switches the clutch 9 in accordance with an instruction from the selection unit 23.

  FIG. 2 is a detailed view of the clutch 11, 25 is a clutch shaft for transmitting the rotational force to the zoom cam, 26, 27 and 28 are bearings, 29 is a key groove provided in a servo pulley, 30 is a push-pull pulley 9 A keyway 31 provided in the shaft 31 is a thrust presser. One end of the servo pulley 10 is supported on the clutch shaft 25 by a bearing 26 and the other end is supported on a push / pull pulley by a bearing 28. On the other hand, one end of the push / pull pulley 9 is supported on the clutch shaft 25 by a bearing 27, and the thrust movement of the series of pulleys and the bearing is regulated by a thrust retainer 31. Therefore, the pulleys 9 and 10 are arranged adjacent to each other and can rotate independently of each other around the clutch shaft 25, and a later-described sverky can move between them.

  32 is a slip key that engages with either the key groove 29 or 30 and moves in the axial direction within the key groove 35 of the clutch shaft 25, 33 is a slider that drives the slip key, and 34 is a screw that fixes the slip key 32 and the slider 33. Here, FIG. 3 is a view showing a cross section AA of FIG. 2, and shows a state in which the sliding key 32 and the key groove 30 of the push-pull pulley 9 are engaged.

  It should be noted that with respect to the slip key 32 and the key groove 29, the engagement points may be provided at a plurality of locations around the circumference.

  Returning to the explanation of FIG. 2 again. Reference numeral 36 denotes a slider operation portion, which is movable in the axial direction when a pin 38 is slidably engaged with the elongated hole portion.

  37 is a spring that urges the slider in the direction of the pulling pulley 9, 39 is a plunger that pushes the slider operation unit 36, 40 is a spring that urges the plunger 39 toward the slider operation unit with respect to the feed screw 41, 41 A feed screw 42 is used to prevent the plunger from coming off, and 43 is a switching motor that rotates the feed screw.

  FIG. 2 shows a state in which the zoom operation is performed by the single-axis two-operation method. By moving the operation rod 14 back and forth, power is transmitted to the wire 16, the outer cylinder 17, and the push / pull pulley 9. The power is transmitted from the slip key 32 to the clutch shaft 25, and the zoom cam 7 is rotated to perform a zoom operation. At this time, since the servo pulley 10 is separated from the push-pull pulley 9 and the clutch shaft 25 by the bearings 26 and 28, the transmission of power does not become an operation resistance for the single-axis two-operation. Conversely, when the sliding key 32 moves to the servo pulley 10 side and engages with the key groove 29, the zoom cam is rotated by the power of the zoom motor 12 to enable servo operation. In the servo operation, the push / pull pulley 9 is not subjected to servo drive resistance because the power transmission is separated from the servo pulley 10 and the clutch shaft 25 by the bearings 27 and 28.

  4 to 7 are diagrams for explaining the switching operation. In FIG. 4, a voltage is applied from the control circuit 24 to the switching motor 43 in order to engage the sub key 32 with the servo pulley 10. The feed screw 41 engaged with the switching motor 43 with a gear moves in the right direction on the paper surface, and moves the plunger 39 and the slider operation unit 36 in the same direction via the spring 40.

  The sliding key 32 moves in the direction of the servo pulley 10 along the key groove 35. However, since the key groove 29 of the servo pulley is not in an engageable position on the circumference, the sliding key 32 abuts on the servo pulley 10. And stop. On the other hand, the feed screw is fed by the switching motor 43 by a moving amount necessary for switching. As a method of determining the necessary movement amount, the stop position of the feed screw 41 is detected by a limit switch or the like, and the switching motor is stopped. At this time, since the spring 40 is compressed, an excessive force by the feed screw 41 is not applied from the feed screw 41 to the servo pulley 10 and the zoom cam 7. At this time, if the compression force of the spring 40 is set larger than the urging force of the spring 37, the slide key 32 is urged in the direction of the servo pulley 10 with a predetermined urging force. When the servo pulley 10 or the push-pull pulley 9 is rotated in this state, the engagement is completed as shown in FIG. 5 when the positions of the slip key 32 and the key groove 29 coincide with each other, thereby enabling the servo operation.

  In the state of FIG. 5, a voltage is applied from the control circuit 23 to the switching motor 43 in order to engage the pulling key 32 with the pulling / pulling pulley 9. The feed screw 41 that engages with the switching motor 43 by a gear moves to the left in the drawing, and is in the state shown in FIG. The sliding key 32 is urged by the spring 37 and moves along the key groove 35 in the direction of the pushing / pulling pulley 9, but the key groove 30 of the pushing / pulling pulley 9 is not in an engageable position on the circumference, so 32 stops while contacting the pulley 9 for pushing and pulling. When the push / pull pulley 9 or the servo pulley 10 is rotated in this state, the engagement is completed as shown in FIG.

  72 is a brake shaft, 73 is a rotation restricting member that engages with a long groove provided on the brake shaft of 72 and restricts rotation of the brake shaft 72, 74 is a motor that moves the brake shaft back and forth, 75 is a chia, 76 is An urging unit that applies a pressing force to the gear 75 to generate a brake torque, 77 is a screw that compresses the urging unit 76, and 78 is a limit switch that limits the movement range of the brake shaft 72.

  FIG. 1 shows a state in which the single shaft 2 is operated, and the outer cylinder 17 and the gear 75 are not engaged and the counterweight is acting. FIG. 8 shows a state during servo operation. At this time, the brake shaft 72 is moved by the motor 74 and the gear 75 is engaged with the gear of the outer cylinder 17.

  As a result, when the lens posture is tilted during servo operation, it is possible to apply a brake so that the counterweight and the operating rod do not move under their own weight.

  When the 1-axis 2-operation method is selected according to the above embodiment, the counterweight can be disconnected from the servo drive system.

[Other embodiments]
FIG. 9 is a drawing showing a second embodiment of the present invention, and 84 is a push-pull pulley, which can input the rotational force of the counterweight and the operation force for one-axis two-operation. According to this embodiment, the same effects as those of the first embodiment can be obtained, and the operation force for one-axis two-operation is transmitted to the push-pull pulley only by the wire 85 without using the counterweight, so that the backlash is small and preferable. A feeling of operation is obtained.

The figure explaining the 1st Example of this invention. The figure explaining a clutch part. Section AA of FIG. The figure explaining the switching state of a clutch. The figure explaining the switching state of a clutch. The figure explaining the switching state of a clutch. The figure explaining the switching state of a clutch. The figure explaining fixation of a counterweight. The figure explaining the 2nd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens main body 2 Focus part optical system 3 Variator optical system 4 Compensator optical system 5 Extender optical system 6 Turret 7 Zoom cam 8 Guide member 9 Pulling pulley 10 Servo pulley 11 Clutch 12 Zoom motor 13 Belt 14 Operation rod 15 Sliding tube 16 Wire 17 Outer cylinder 18 Belt 19 Rotating shaft 20 Counterweight 21 Engaging member 22 Engaging member 23 Operation method selection unit 24 Control circuit 25 Clutch shaft 26 Bearing 27 Bearing 28 Bearing 29 Keyway 30 Keyway 31 Thrust retainer 32 Slip key 33 Slider 34 Screw 35 Keyway 36 Slider operation section 37 Spring 38 Pin 39 Plunger 40 Spring 41 Feed screw 42 Retaining stopper 43 Switching motor 70 Actuator 71 Guide member 72 Brake shaft 3 rotation restricting member 74 motor 75 gear 76 biasing means 77 screw 78 limit switch 79 with the outer cylinder 80 the plunger 81 urging means 82 gear shaft 83 motor 84 push and pull pulley 85 wire

Claims (5)

A clutch capable of selecting either a single-axis two-operation method or a servo operation method;
A television lens, comprising: a counterweight for preventing a change in position of the optical system due to a change in posture; and a counterweight disposed on a power transmission member side by a one-axis two-operation system of the clutch.   2. The television lens according to claim 1, wherein the operating force of the 1-axis 2-operation system is transmitted to the power transmission member side of the clutch by the 1-axis 2-operation system via the output shaft of the counterweight.   2. The television lens according to claim 1, wherein an operation force of a single axis and two operation method and an output of a counterweight are inputted in parallel to a power transmission member side of the clutch by a single shaft and two operation method.   4. The television lens according to claim 1, 2, 3 or 3, wherein the optical system is a zoom system.   4. The television lens according to claim 1, 2, 3 or 3, wherein the optical system is a focus system.

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