JPS6198311A - Lens driver - Google Patents

Abstract

PURPOSE:To improve the handling of a device by forming a control means for controlling the rotational frequency of a motor so as to vary it when only a transmission means for driving a power modification means to be engaged/ disengaged with/from the transmission means through the motor at the engagement with the power modification means is engaged. CONSTITUTION:When the pushing force of a zooming operation lever 50a is removed, an arm 50 is restored to the center point by the tensile force of a tensile spring 57 and a zoom switch 58 is turned off, so that a motor 24 is stopped and a pulley 56 is separated from a zoom ring 25 to stop the rotation of the zoom ring 25. When the lever 50a is pressed in the reverse direction against the arrow 60, a pulley 55 is abutted upon the zoom ring 25, the zoom ring 25 is rotated in the counterclockwise direction through gears 51, 53 and the pulley 55, so that the focal distance is moved to the telescopic side. When a focus ring 22 is not driven and only the zoom ring 25 is driven, the rotational frequency of the motor 24 can be optionally set up by operating an operation button 31a connected to a control circuit 31 to vary the turning speed of the zoom ring 25.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a lens driving device that can be used in a zoom lens of a video camera or the like.

Conventional Structures and Their Problems In recent years, with the spread of video cameras, there has been a demand for zoom lenses with autofocus and electric zoom functions.

Hereinafter, a conventional lens driving device and device will be described with reference to the drawings. FIG. 1 is a diagram showing the main parts of a conventional lens driving device, in which a focus ring 2 for holding a focusing lens is provided at the front of a lens unit 1.
The focus ring 2 has a spur gear 3 on its outer periphery. Since the spur gear 3 meshes with the spur gear 6 press-fitted into the focus motor 4, the focus ring 2 can be driven by the focus motor 4. Further, a distance measuring sensor 6 composed of an infrared LED (light emitting diode), a light receiving element, etc. for measuring the distance to the subject is provided outside the lens unit 1, and is connected to a distance measuring circuit 7. There is. The motor drive circuit 8 uses the distance signal to the subject obtained by the distance measuring circuit 7 and the focus ring 2.
A predetermined voltage is supplied so that the seven orcus motor 4 rotates in a direction in which the difference between the two signals becomes smaller. Furthermore, lens unit 1
A zoom ring 9 for driving a variable magnification lens is provided in the middle of the zoom ring 9, and meshes with a spur gear 10 provided on the outer periphery of the zoom ring 9 and a spur gear 12 press-fitted into the zoom motor 1. Therefore, zooming can be performed by moving the variable magnification lens in forward and reverse directions according to the polarity of the voltage supplied to the zoom motor 1.

However, in the above configuration, dedicated motors are required for focusing and zooming, which increases the weight and increases the cost.

Purpose of the Invention The purpose of the present invention is to provide a lightweight, inexpensive, and easy-to-use camera that has autofocus and electric zoom functions.
/z drive device.

l'□ Structure of the Invention The lens driving device of the present invention includes a motor, a focusing means for focusing an optical image of a subject, a variable magnification means for changing the magnification of an optical image of a subject, and a focusing means and a motor. a first transmission means for driving the focusing means by the motor when the first transmission means is disengaged from the transmission means and engaged with the zooming means; The motor is configured to include a second transmission means for driving and a control means for variably controlling the output rotation speed of the motor when only the second transmission means is engaged. Since focusing and zooming can be performed and the speed of zooming can be varied, it is possible to provide a lens 1 driving device that is easy to use.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a configuration diagram of main parts of a lens driving device according to an embodiment of the present invention, in which a focusing lens is held in the front part of the lens unit 21 and rotated to move the lens in the optical axis direction. The focus ring 22 has a movable focus ring 22, and the power of a motor 24 having a built-in deceleration mechanism and rotating in a fixed direction can be transmitted to the focus ring 22 via a focus ring drive mechanism 23. Similarly, the rear part of the lens unit 21 has a zoom ring 26 for operating the variable magnification lens, and the rotation of the motor 24 can be transmitted to the zoom ring 26 via the zoom ring drive mechanism 26. Also, outside the lens unit 21, there is a distance measuring sensor 2 configured with an infrared 14D (light emitting diode) and a light receiving element for measuring the distance to the subject.
7 is provided and connected to the distance measuring circuit 272L. The focus ring 22 has a built-in encoder (not shown) for detecting the focusing distance of the focusing lens, and the out-of-focus detection circuit 28 compares the signal from the encoder and the signal from the distance measurement circuit 271L. However, if there is a predetermined difference between the distance to the subject determined by the distance measuring circuit 27& and the distance currently focused by the focusing lens, the solenoid 46 is driven by the solenoid drive circuit 29, and the focus ring drive mechanism is activated. 23 and rotates the motor 24 via the detection circuit 30 and control circuit 31. The detection circuit 30 is connected to a solenoid drive circuit 29 and a zoom switch 58 provided in the zoom ring drive mechanism 26 .
The operating state of the zoom ring drive mechanism 26 is detected, and when only the zoom ring drive mechanism 26 is operated, the control circuit 31 is configured to vary the rotation speed of the motor 24. Note that the control circuit 31 has an operation knob 3.
1a is connected, and the rotation speed of the motor 24 can be set to an arbitrary value using the operation knob 312L, and the zoom speed can be freely varied. Further, since the control circuit 31 can be easily realized by using various rotation speed control means that are already known techniques, details thereof will be omitted.

Next, the detailed structure of the focus ring drive mechanism 23 will be explained using FIGS. 3 and 4. 3 is a front view of the focus ring drive mechanism 23 seen from the front of the lens unit 21, and FIG. 4 is a sectional view taken along the line X--X in FIG. 3. The drive shaft 32 is held by a bearing 33 and driven by a motor 24. Further, an arm 34 is rotatably supported on the outer circumference of the bearing 33, and shafts 36, 36, 37 are mounted on the arm 34, and a gear 38 press-fitted into the drive shaft 32 is driven by the shaft 36. A gear 39 that is rotatably supported and a gear 40 that is rotatably supported by the shaft 37 mesh with each other. The gear 39 meshes with a gear 41 rotatably supported by the shaft 36, and the gear 41 and the gear 40 are connected to a pulley 42 having a rubber ring on the outer periphery.
It has an integrated structure with 43. A tension spring 44 is stretched around the arm 34, and the tension spring 44 normally holds the pulleys 42, 43 in a position where they do not touch the focus ring 22. It can be rotated.

FIG. 6 shows details of the zoom ring drive mechanism 26.
4, and a cross-sectional view of the zoom ring drive mechanism 26 is the same as that of the focus ring drive mechanism 23 in FIG. 4, so it will be omitted. In Fig. 6, shafts 47, 48
．． An arm 50 with an erected shaft 49 is rotatably supported around the drive shaft 32, and a gear 61 fixed to the drive shaft 32.
meshes with gears 62 and 53, gear 62 meshes with gear 54
It meshes with. Further, the gears 53, 64 are integrally constructed with a pulley 55, 56 having a rubber ring on the outer periphery, and are rotatably held by a shaft 48, 49. A tension spring 57 is still tensioned on the arm 5o, and the pulley 55, 56 is normally held in a position where it does not touch the zoom ring 26 by the tension spring 67, and the zoom operation lever SOa provided on the arm 60 is operated. By this, it is possible to rotate the arm 6o, and when the arm 50 rotates, the protrusion 5 provided on a part of the arm 50
i) b is configured to press the zoom switch 68; Note that this zoom switch 68 is connected to the detection circuit 30.
It is connected to the.

Lens drive of this example configured as above
! The operation of the device will be explained below. First, driving of the focus ring 22 will be explained. When the current focus distance of the focusing lens is infinite, when photographing a nearby subject (for example, the distance to the subject is 3 m),
The distance sensor 27 measures this distance, and the out-of-focus detection circuit 28 detects that it is different from the focusing distance of the focusing lens, and the solenoid drive circuit 29 energizes the solenoid 46 and the control circuit 31. constant voltage to motor 24
Offered to.

and rotate the motor 24 in the direction of arrow 69 (counterclockwise) shown in FIG. At this time, since the solenoid 46 is suctioning, the arm 34 rotates counterclockwise, and the pulley 42 comes into contact with the focus ring 22, causing the focus ring 22 to rotate clockwise via the gear 38.39141. move. Therefore focus ring 2
The focusing distance of the focusing lens moves as the lens rotates, and when the focusing lens moves until it matches the distance to the subject measured by the range sensor 27, the solenoid drive circuit 29 energizes the solenoid 46. When the current is cut off, the arm 34 returns to the center point due to the tension of the tension spring 44, and the pulley 42 separates from the focus ring 22, and at the same time, the rotation of the motor 24 also stops. Also, when the focusing lens focuses on a short distance and the subject is far away, the solenoid 46 attracts suction, contrary to the above case, the arm 34 rotates clockwise, and the pulley 43 engages the focus ring 22. At the same time as the contact, the motor 24 also rotates, and the gear 38 moves in the direction of the arrow 69 (
counterclockwise). Therefore, the focus ring 22
It rotates counterclockwise via the I/i gear 40 and pulley 43.

Next, driving of the zoom ring 26 will be explained. 6th
In the figure, when the zoom operation lever SOa is pressed in the direction of the arrow 60, the projection sob presses the zoom switch 68, this is detected by the detection circuit 3o, and the control circuit 3
1 supplies a predetermined voltage to the monitor 24, the motor 24 rotates, the arm 60 moves counterclockwise, and the pulley 56 comes into contact with the zoom ring 26. As the motor 24 rotates, the gear 61 rotates counterclockwise, the zoom ring 25 rotates clockwise via the gears 52 and 54 and the pulley 56, and the variable magnification lens moves to change the focal length to the wide-angle side. Move to.

When the pressing force of the zoom operation lever 50a is removed, the arm 6o returns to the midpoint due to the tension of the tension spring 67, the zoom switch 58 is turned off, the motor 24 is stopped, and the pulley 56 and zoom ring 26 are separated. The rotation of the zoom ring 26 stops. Contrary to the above, the zoom operation lever 60! When L is pressed in the direction opposite to the arrow 60, the fullie 55 and the zoom ring 25 come into contact, and the zoom ring 26 rotates counterclockwise via the gears 61, 63 and the pulley 55, changing the focal length to the telephoto side. Move to. Here, when the focus ring 22 is not driven and only the zoom ring 26 is driven, the rotation speed of the motor 24 can be freely set by operating the operation knob 31a connected to the control circuit 31. It becomes possible to
It is possible to vary the rotation speed (zoom speed) of the zoom ring 26.

As described above, according to this embodiment, it is possible to perform focusing and zooming with the same motor, and the speed of zooming can be varied, so it is possible to vary camera work.
It is possible to provide lenses and drive devices that are easy to use.

In addition, in the above-mentioned embodiment, a case was explained in which a focus ring was used as a focusing means and a zoom ring was used as a zooming means, but the ring is not limited to this, and has functions of focusing and zooming. Anything is fine.

Effects of the Invention As is clear from the above description, the present invention includes a motor and a focusing means for focusing an optical image of a subject, a magnification changing means for changing the magnification of an optical image of a subject, and a focusing means for focusing an optical image of a subject. a first transmission means that is in a disengaged relationship with the zooming means and is engaged with the focusing means to drive the focusing means with a motor; a second transmission means for controlling the motor; and a control means for variably controlling the rotational speed of the motor when only the second transmission means is engaged.
(Since the configuration includes the following, it is possible to perform focusing and zooming with the same motor, and the speed of zooming can be freely varied, providing an easy-to-use lens drive device with stable camera work. can do.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the main parts of a conventional lens driving device, and FIG. 2 is a diagram showing the main parts of a lens driving device according to an embodiment of the present invention.
3 is a front view of the focus ring drive mechanism of the same embodiment, FIG. 4 is a sectional view taken along the line X-X of FIG. 3, and FIG. 6 is a front view of the zoom ring drive mechanism of the embodiment of the present invention. be. 22...Focus ring, 23...
Focus ring drive mechanism, 24... River motor, 26
...Zoom ring, 26...Zoom ring drive mechanism, 28...Out-of-focus detection circuit, 29...
....renoid, drive circuit, 30...detection circuit, 31...control circuit, 46.46...
...Nlenoid, 60a...Zoom operation lever, 68...Zoom switch. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 5

Claims (1)

[Claims] (1) a motor, a focusing means for focusing an optical image of a subject, and a variable magnification means for varying the magnification of an optical image of a subject;
a first transmission means that is in an engaged/disengaged relationship with the focusing means and is engaged therewith to drive the focusing means by the motor; and a first transmission means that is in an engaged/disengaged relationship with the zooming means and is engaged therewith and a control means for variably controlling the output rotation speed of the motor when only the second transmission means is engaged. A lens drive device.