JP2000338381A - Optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the back driving of a motor-drive displacing means which does not have sufficient hold torque and to make the device small-sized and low-cost. SOLUTION: On the outer peripheral surface of an idler shaft 24 which supports an idler gear 20, a friction ring 25, a pressure spring 26, and a pressure ring 27 are provided in order adjacently to the idler gear 20, which is loaded. A control circuit for controlling a DC motor 23 comprises a control part which is connected to the DC motor 23, a command part which gives a speed command to the control part, and a speed sensor which detects the rotating speed of the DC motor 23 and feeds the rotating speed of the DC motor 23 back to the control part. In motor driving operation, the control circuit controls the rotating speed of the DC motor 23 to zero to restrict the rotation of the driving gear 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device such as a television lens device used by being mounted on a television camera, for example.

[0002]

2. Description of the Related Art As shown in FIG. 10, a conventional optical device of this type includes a drive unit 62 in an apparatus main body 61, and a housing 63 of the apparatus main body 61 allows a movable lens group to move freely in the optical axis direction. Built-in. The housing 63 includes a manual operation system for manually operating the movable lens group, and an electric operation system for electrically operating the movable lens group. The manual operation system has an operation ring 64, and the drive unit 62 is an electric operation system. Built-in drive motor, control circuit, etc. The lens barrel 63
Has built-in optical means such as a diaphragm in addition to the movable lens group, and also has operation means for the optical means.

[0003] Such a conventional optical device often has a clutch mechanism having a switching lever for switching between manual operation and electric operation, but some optical devices do not have this type of clutch mechanism. is there. In the latter case, a differential mechanism that combines a drive amount by a manual operation and a drive amount by an electric operation is employed, and the operating mechanism drives the moving lens group based on the combined drive amount.

In this case, in order to transmit the drive amount of the manual operation system to the movable lens group, it is necessary to restrict the electric operation system from back driving during manual operation. From such a necessity, a conventional optical device having a differential mechanism employs a vibration wave motor as a drive motor, and the back torque of the electric operation system is prevented by the holding torque of the vibration wave motor.

[0005]

However, when the vibration wave motor is employed, the back drive of the electric operation system can be prevented by a sufficient holding torque.
In addition, there is a problem that the diameter of 3 increases and the control circuit becomes complicated, thereby increasing the manufacturing cost.

An object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide a small and inexpensive optical device which can prevent the back drive even when the electric displacement means having no sufficient holding torque is employed.

[0007]

According to the present invention, there is provided an optical apparatus comprising: a manual displacement means for manually displacing an optical means held in a housing; and an electric displacement means for displacing by an electric operation. And a displacement synthesizing means for synthesizing the displacement of the manual displacement means and the displacement of the electric displacement means, and a regulating means for regulating the operation of the electric displacement means during the manual operation.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS. FIG. 1 is a partial cross-sectional view of the first embodiment, FIG. 2 is a cross-sectional view taken along line AA of FIG.
FIG. 2 is a cross-sectional view along the line BB in FIG. 1, and the optical device is, for example, a television lens device. The moving lens group 1 for focusing is held by a lens barrel 2, and the lens barrel 2 is movable in the direction of the optical axis within the rotating barrel 3.
At least three roller members 4 are provided on the outer peripheral surface of the lens barrel 2.
These roller members 4 are provided with curved grooves 3 of the rotary cylinder 3.
a, a straight groove 6 of a fixed barrel 6 constituting the lens housing 5
a.

A scale ring 7 is provided on the outer periphery of the fixed cylinder 6.
An outer cylinder 8 is provided on the outer circumference of the scale ring 7. Rotating cylinder 3
A connecting pin 9 is projected from an outer peripheral surface of the scale ring 7, and the connecting pin 9 is engaged with a groove 7 a of the scale ring 7 via a groove 6 b of the fixed cylinder 6. Thus, the rotation of the scale ring 7 is controlled by the connecting pin 9.
Is transmitted to the rotary cylinder 3 through the lens unit, and the movable lens group 1 can be moved. A scale 7b indicating the lens position is engraved on a part of the scale ring 7, and the scale 7b is made visible from the transparent window 10 of the outer cylinder 8. A gear portion 7c is provided on a part of the scale ring 7, and the gear portion 7c is connected to a potentiometer 14 via a detection idler gear 12 and a detection gear 13 stored in a drive unit 11 so that the lens position can be detected. Have been.

At one end of the scale ring 7, an operation ring 15 as a manual lens displacement means is provided on the outer peripheral surface of the fixed cylinder 6. A drive gear 16 is provided between the inner peripheral surfaces of the cylinder 8.
The inner peripheral surface 15a of the operation ring 15 is pressed at three points on the entire circumference by a leaf spring 17 as a pressing means, and a predetermined load is applied to the operation ring 15. The support shaft 18 is provided in at least three concave portions 7d provided on the outer peripheral surface of the scale ring 7.
The support shaft 18 is provided with a synthetic gear 19 made of an elastic body.
Is supported. The gear portion 15b on the side surface of the operation ring 15 and the gear portion 16a on the side surface of the drive gear 16 are meshed with the composite gear 19 so as not to rattle. That is, the scale ring 7, the support shaft 18, and the combined gear 19 constitute a displacement amount combining unit that combines the drive amounts of the manual operation and the electric operation.

A DC motor 23 is connected to a gear portion 16 b on the outer peripheral surface of the drive gear 16 via an idler gear 20, a motor gear 21 and a gear head 22. That is,
The drive gear 16, the idler gear 20, the motor gear 21, the gear head 22, and the DC motor 23 constitute an electric lens displacement unit.

If there is backlash in the motorized lens displacement means, the operating ring 15 is
In order to drive the motorized lens displacing means by the amount of backlash, the operation ring 15 starts rotating while rattling, and the movable lens group 1 moves with a time lag. To eliminate such backlash, idler gear 2
0 is always loaded. That is, on the outer peripheral surface of the idler shaft 24 supporting the idler gear 20, a friction ring 25 and a pressure spring 26 are disposed adjacent to the idler gear 20.
And a pressure ring 27 are sequentially provided.
Is pressed against the idler gear 20 by the urging force of the pressure spring 26. At this time, if the frictional force between the idler gear 20 and the friction ring 25 is large, the power consumption of the DC motor 23 increases, so that the frictional force is preferably small.

When the load on the motorized lens displacement means is large, when the operation ring 15 rotates, the combined gear 19
When the load on the electric lens displacing means is small, the scale ring 7 does not rotate and the drive gear 16 rotates. When the driving gear 16 rotates, the driving force of the operation ring 15 is not transmitted to the movable lens group 1, so that the rotation of the driving gear 16 needs to be restricted. Further, since the operating ring 15 itself does not have an operating end, the operating ring 15 drives the drive gear 16 after the connecting pin 9 reaches the operating end by operating the operating ring 15. At this time, if the drive gear 16 rotates easily, the operator cannot recognize that the movable lens group 1 has reached the operating end, and the usability is significantly reduced.

For this reason, in the first embodiment, in order to restrict the rotation of the drive gear 16, the DC motor 2
3 can be controlled to be zero.
That is, FIG. 4 shows a state in which the DC motor 23 is controlled, and the control circuit 31 connected to the DC motor 23
A control unit 32 connected to the motor 23;
And a speed sensor 34 for detecting the rotation speed of the DC motor 23. The rotation speed of the DC motor 23 is fed back to the control unit 32.

At the time of manual operation, the command unit 33 issues a command to reduce the rotation speed of the DC motor 23 to zero,
3 regulates the rotation of the drive gear 16. Thus, the rotation of the operation ring 15 is transmitted to the composite gear 19, and the composite gear 1
The rotation of 9 is transmitted to the scale ring 7, and the scale ring 7 rotates to move the movable lens group 1.

At the time of electric operation, the command unit 3 of the control circuit 31
3 issues a command not to regulate the speed of the DC motor 23,
The driving force of the C motor 23 is the gear head 22, the motor gear 2
1, transmitted to the drive gear 16 via the idler gear 20,
The driving gear 16 rotates and the composite gear 19 rotates. At this time, although the composite gear 19 is engaged with the operation ring 15, the operation ring 15 receives a predetermined load from the leaf spring 17, so that the operation ring 15 does not rotate, and only the scale ring 7 rotates. For this reason, the rotation of the scale ring 7 is transmitted to the rotary barrel 3 via the connecting pin 9, and the rotary barrel 3 rotates to move the movable lens group 1.

When the manual operation is performed during the electric operation, the operation ring 15 and the drive gear 16 meshed with the composite gear 19 rotate simultaneously, so that the scale ring 7 is operated by the operation ring 15.
It rotates based on the combined amount of rotation of the drive gear 16 and the rotation amount of the drive gear 16. Therefore, the movable lens group 1 is
It moves according to the combined amount of the C motor 23.

In the first embodiment, the speed of the DC motor 23 is released not only at the time of the electric operation but also at the time of the manual operation, even when the DC motor 23 having no holding torque like the vibration wave motor is used. Without that speed can be controlled to zero. Therefore, the rotation of the drive gear 16 can be restricted,
The driving force of the operation ring 15 can be transmitted to the movable lens group 1,
It is possible to quickly switch between manual operation and electric operation without performing any special operation. In addition, since a load is applied to the idler gear 20 to reduce backlash, rattling and time lag are eliminated, and manual operability is improved. Further, since there is no conventional clutch mechanism, no troublesome sound is generated.

When the backlash of the motorized lens displacement means is small, it is needless to say that it is not necessary to apply a load to the idler gear 20.

FIG. 5 shows a second embodiment. The operating ring 15 and the driving gear 16 of the first embodiment are composed of an operating ring 15 'and a driving gear 16' which do not have a gear portion 15b and a gear portion 16a, respectively. The composite gear 19 of the first embodiment is a roller member 41. Further, the friction ring 25, the pressure spring 26, and the pressure ring 27 of the first embodiment are removed, and the drive gear 16 'is urged toward the roller member 41 by the friction ring 42, the disc spring 43, and the pressure ring 44. Have been. Thereby, one end face 15c of the operation ring 15 'and the drive gear 1
One end surface 16c of 6 'is pressed against the outer peripheral surface of roller member 41, and the driving force of operation ring 15' and drive gear 16 'is transmitted to roller member 41 by friction.

In the second embodiment, the operation ring 15 '
The one end surface 15c of the drive gear 16 'and the one end surface 16c of the drive gear 16' are pressed against the outer peripheral surface of the roller member 41, so that backlash between them is reduced. Further, since the urging force of the disc spring 43 presses the other end surface 15d of the operation ring 15 'against the step 6c of the fixed cylinder 6, the operation ring 15' does not rotate during the electric operation, and the movable lens group 1 moves. At the time of manual operation, the same operation and effect as those of the first embodiment can be obtained.

FIG. 6 shows a third embodiment. Instead of the idler gear 20 of the first embodiment, an idler gear 45 having an engaging portion 45a and an engaging portion 4 capable of engaging with the engaging portion 45a are provided.
A regulating member 46 having 6 a is supported by the idler shaft 24. The regulating member 46 is urged toward the idler gear 45 by urging means (not shown).
5 and the regulating member 46 are engaged via engaging portions 45a, 46a. The regulating member 46 is controlled by an electromagnetic clutch 47.
It can be separated from the idler gear 45.

As shown in FIG. 7, an electric operation member 48 is connected to the electromagnetic clutch 47. The electric operation member 48 is attached to the drive unit 11, and a command signal for controlling the DC motor 23 is output according to the operation amount of the electric operation member 48. Further, between the electromagnetic clutch 47 and the electric operation member 48, there is provided an electric operation determining means 49 for determining whether the operation is a manual operation or an electric operation. Have been.

FIG. 8 is a graph showing the operation amount of the electric operation member 48 and the intensity of the output signal. The reference output value is output when the electric operation member 48 is not operated, and the operation is performed when the electric operation member 48 is operated. An output value corresponding to the direction and the operation amount is output. Then, the electric operation determining means 49
Is determined to be a manual operation when the output signal is at or near the reference output value, and is determined to be an electric operation when the output signal is other than near the reference output value, and controls the electromagnetic clutch 47. I have.

When the electric operation discriminating means 49 discriminates the manual operation, the electromagnetic clutch 47 is turned off in a non-energized state, the regulating member 46 moves to the idler gear 45 side, and the engaging portion 45a of the idler gear 45 and the regulating member 45a. 46 engaging portions 4
6a engage. Thus, the idler gear 45 regulates the rotation of the drive gear 16 ', and the movable lens group 1 moves when the operation ring 15' rotates.

On the other hand, when the electric operation determining means 49 determines that the operation is an electric operation, the electromagnetic clutch 47 is turned on, and the regulating member 46 is separated from the idler gear 45, so that the idler gear 45 can rotate. Then, the driving force of the DC motor 63 is transmitted to the driving gear 16 'via the gear head 62, the motor gear 61, and the idler gear 45, and the operation ring 15' rotates to move the movable lens group 1.

In the third embodiment, the idler gear 45, the regulating member 46 and the electromagnetic clutch 47 are employed as means for connecting / disconnecting a part of the electric lens displacement means. As long as it is a member, a member other than the idler gear 45 may be used. In addition, there is no problem even if electric regulating means such as a solenoid other than the electromagnetic clutch 47 is used. Further, the electric operation determining means 49 determines whether the operation is a manual operation or an electric operation based on a command signal of the electric operation member 48, and it is also possible to determine the command operation from a demand device provided near the lens device or a command signal from the camera. It is also possible to respond to command signals from these multiple command sources.

FIG. 9 shows a fourth embodiment, in which a DC motor 2
The stop state of No. 3 is configured to be specified using the back electromotive force. That is, when the DC motor 23 is driven from the output side, the coil of the conductor rotates in the magnetic field generated by the permanent magnet of the DC motor 23, and the back electromotive force is generated in the DC motor 23. On the other hand, a predetermined torque is required to drive the DC motor 23 from the output shaft side. Since the magnitude of the back electromotive force is determined by the resistance of the magnet and armature of the DC motor 23, the resistance between the motor terminals, and the winding conditions of the coil, a back electromotive force generating circuit is configured in the fourth embodiment. ing.

That is, the electric operation member 48 is connected to the control circuit 50, and the resistor 51 is connected between the DC motor 23 and the control circuit 50. Circuit switching means 52 for switching the circuit connected to the DC motor 23 manually and electrically is connected to the electric operation determination means 49. The terminal 53 of the control circuit 50 and the terminal 54 of the resistor 51 are switched by a switch piece 55 of the circuit switching means 52.

At the time of electric operation, the circuit switching means 52 connects the switch piece 55 to the terminal 53 of the control circuit 50, and the control circuit 50 controls the DC motor 23. During manual operation,
The circuit switching means 52 connects the switch piece 55 to the terminal 5 of the resistor 51.
4 to switch the resistance value between the terminals 53 and 54 to a predetermined value of the resistor 51, and connect the control circuit 5 to the terminals 53 and 54.
The drive voltage generated from 0 is not input. That is, at the time of manual operation, the back electromotive force generation circuit including the DC motor 23, the resistor 51, and the circuit switching means 52 causes the DC motor 23 to generate the back electromotive force.

In the fourth embodiment, the terminals of the DC motor 23 can be short-circuited instead of the resistor 51. In this case, the back electromotive force generated by the DC motor 23 becomes maximum. . If the resistance value of the control circuit 50 is equal to the resistance value of the resistor 51, the circuit switching means 52 can be omitted.

Although the first to fourth embodiments have been described with respect to driving the movable lens group 1 for focusing, it can be applied to drive a zoom lens, an iris, a pan head device and the like. Not even.

[0033]

As described above, since the optical device according to the present invention has the regulating means for regulating the operation of the electric displacement means at the time of manual operation, even if the electric displacement means which does not have a sufficient holding torque is employed. , That back drive can be prevented. Therefore, a DC motor other than the vibration wave motor can be used, and downsizing and cost reduction can be achieved.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a first embodiment.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a control circuit diagram.

FIG. 5 is a partial cross-sectional view of the second embodiment.

FIG. 6 is a partial sectional view of a third embodiment.

FIG. 7 is a layout view of an electric operation member.

FIG. 8 is a graph showing the operation amount of the electric operation member and the intensity of the output signal.

FIG. 9 is a control circuit diagram of a fourth embodiment.

FIG. 10 is a side view of a conventional example.

[Description of Signs] 1 Moving lens group 2 Lens barrel 15, 15 'Operation ring 16, 16' Drive gear 19 Synthetic gear 20, 45 Idler gear 21 Motor gear 22 Gear head 23 DC motor 25 Friction ring 26 Pressure spring 27 Pressure ring 31, 50 control circuit 32 control unit 33 command unit 34 speed sensor 41 roller member 42 friction ring 43 disc spring 44 pressure ring 46 regulating member 47 electromagnetic clutch 48 electric operation member 49 electric operation determination means 51 resistance 52 circuit switching means 53, 54 Terminal 55 Switch piece

Claims (7)

[Claims] 1. A manual displacement means for displacing an optical means held in a housing by a manual operation, an electric displacement means for displacing by an electric operation, and a displacement of the manual displacement means and a displacement of the electric displacement means are combined. An optical device comprising: a displacement amount synthesizing unit that performs the manual operation; and a regulating unit that regulates an operation of the electric displacement unit during the manual operation. 2. The optical device according to claim 1, wherein said regulating means has a function of stopping operation of a drive source of said electric displacement means. 3. The optical device according to claim 2, wherein said regulating means has a function of maintaining an operation speed of said drive source at zero. 4. The optical device according to claim 2, wherein the regulating unit has a function of stopping the operation of the driving source using a back electromotive force. 5. The optical device according to claim 2, further comprising: means for generating a load on a part of said electric displacement means. 6. The apparatus according to claim 1, further comprising a determination unit that determines whether the operation is manual or electric, wherein the restriction unit has a function of releasing or releasing the restriction based on a determination result of the determination unit. The optical device of claim 7. The optical device according to claim 6, wherein the determination means determines the manual operation when the command signal to the drive source is at a reference value, and determines the electric operation when the command signal is not the reference value. .