JPH0617929B2 - Lens moving device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens moving device applied to a video camera or the like.

Conventional example and configuration and its problems A conventional zooming mechanism using a belt of a lens barrel includes an operating ring that engages with a cam barrel formed with a cam that drives the lens moving frame in the optical axis direction by rotating. There is something that moves the lens by stretching the belt. This will be described with reference to FIG.

FIG. 1 is a sectional view of a main part of a conventional zoom lens barrel using a belt. The focusing lenses L1, L2 and L3 are mounted on the focusing frame 2 and fixed by the L1 lens retainer 3 via the spacer 4. The helicoid screw 1a provided on the fixed barrel 1 and the helicoid screw 2 provided on the focusing frame 2
a is screwed and the focusing frame 2 is rotated around the optical axis to move the focusing lenses L1, L2 and L3 in the optical axis direction. The variable power lenses L4, L5 and L6 are inserted into the first lens moving frame 13 and the L4 lens retainer 14
The screw portion 14a of the first lens moving frame 13
It is fixed by screwing into c. Correction lens L7
Is inserted into the second lens moving frame 15, and the holding ring 16
On the inner circumference of the second lens moving frame 15
Fixed by inserting into. The guide pole 8 is inserted into the hole 13a provided in the first lens moving frame 13, the guide pole 9 is inserted into the hole 15a provided in the second lens moving frame 15, and the first and second Notch parts 13b provided in the lens moving frames 13 and 15 of
The guide pole 10 is engaged with 15b. The guide poles 8, 9 and 10 have a hole 1a formed in the fixed cylinder 1 at one end.
Hole 11 formed in the pole support plate 11 at the other end.
It is supported by being fitted in a. The pole support plate 11 is formed with a protrusion (not shown) protruding to the outer peripheral portion, and this is a notch (not shown) formed in the fixed cylinder.
The holes 11a for supporting the guide poles 8, 9 and 10 are brought into phase with each other by engaging with. The pole support plate 11 is fixed by inserting the holding ring 12 into the inclined surface portion 1b provided on the inner circumference of the fixed barrel 1. The first cam follower 17 planted in the first lens moving frame 13.
Engages with a first cam groove 6a formed in the cam barrel 6. Similarly, the second cam follower 18 planted in the second lens moving frame 15 is engaged with the second cam groove 6b formed in the cam barrel 6. The zoom ring 19 is attached to the fixed barrel 1.
Is rotatably fitted around the optical axis. An operation knob 21 is planted in the zoom ring 19. A long groove 19a in the optical axis direction is formed on the inner peripheral surface thereof.
The pin 20 planted in the cam barrel 6 is engaged with 9a.
Further, a belt 23 is stretched between a large pulley 19c formed integrally with the zoom ring 19 and a pulley 28 planted on a rotary shaft 27a of the zoom motor 27. Master holding frame 26 for holding a master lens (not shown)
Is inserted into a holding portion 22a formed on the support member 22 and fixed at a predetermined position. The support member 22 fixes the zoom motor 22.

The zooming operation of the lens barrel configured as described above will be described below. When the rotation of the zoom motor 27 is transmitted to the large pulley 19c via the belt 23, the zoom ring 19 rotates around the optical axis. Then, the pin 20 engaged with the long groove 19a of the zoom ring 19 is driven to rotate the cam barrel 6 around the optical axis. First lens moving frame 13
The first cam follower 17 and the second cam follower 18 implanted in the second lens moving frame 15 move in the optical axis direction along the engaging cam grooves 6a and 6b, respectively. . In this way, zooming is performed by driving the variable lenses L4, L5, L6 and the correction lens L7 in the optical axis direction.

However, in the above structure, the inner diameter of the large pulley 19c cannot be made smaller than the optical path diameter 19'b.
Therefore, there is a problem that the total belt length becomes long, the belt winding angle of the motor output side pulley becomes small, and the transmission torque cannot be made large.

OBJECT OF THE INVENTION It is an object of the present invention to provide a lens moving device which is small in size and is capable of efficiently moving a lens by driving a belt.

The lens moving device of the present invention is capable of moving in the optical axis direction.
And a second lens moving frame, and a cam that drives the first and second lens moving frames and rotates in a plane parallel to the optical axis.
It is composed of a motor having a rotation axis parallel to the rotation axis of the cam, and a transmission means for transmitting the rotation of the motor to the cam via a belt. Since it can be determined regardless of the optical path diameter, it is an efficient lens moving device by belt transmission.

Description of Embodiments An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a perspective view of a main part of the lens moving device according to the embodiment of the present invention. The focusing lens group holding frame 34 holds the focusing lens group A, and is fitted to the inner cylinder side of a holding ring 36 formed integrally with the lens substrate 30. An end face cam (not shown) formed on the end face of the focus holding frame 34
The focusing lens holding frame 34 is held by the holding ring 36 by being pressed by the pressing spring portion 35 a of the connecting member 35. The hole 37a of the first lens moving frame 37 is inserted into the guide pole 42 supported by the lens substrate 30, and the lens substrate 30 is formed in a notch (not shown) for preventing rotation.
It is supported on the lens substrate 30 so as to be movable in the optical axis direction by engaging the guide pole 43 supported by the lens. Similarly, the second lens moving frame 38 is also movably supported on the lens substrate 30 by inserting the guide pole 43 into the hole 38a and engaging the notch 38b with the guide pole 42. . The cam plate 31 has a groove 32 formed for moving the first lens moving frame 37 in the optical axis direction and a cam groove 33 formed for moving the second lens moving frame 38 in the optical axis direction. It has a shaft (not shown) implanted in the lens substrate 30 and is rotatably mounted in a plane parallel to the optical axis. The fixed lens D is mounted on a fixed frame 39 which is positioned and fixed on the lens substrate 30. Master lens group (not shown), filter 41
Is attached to a support base 44 formed integrally with the lens substrate 30.

FIG. 3 is a plan view showing a transmission means of the lens moving device, and FIG.
The figure is a sectional view thereof. The cam plate 31 is rotatably fitted on a shaft 47 that is planted in the lens substrate 30. The cam plate 31 is integrally formed with the internal gear 31a, and the gear 5
It bites with 2. The gear 52 is rotatably fitted to the shaft 48 planted in the lens substrate 30, and integrally forms the gear 51 that meshes with the gear 54. The gear 54 is planted in the lens substrate 30 and rotatably fitted in the shaft 49, and integrally forms a large pulley 55. A belt 56 is stretched between the large pulley 55 and a small pulley 58 press-fitted into a rotary shaft 57 of the zoom motor 59, and the rotation of the zoom motor 59 is transmitted from the belt 56 to a gear train to form a cam plate. 31 will rotate.

The operation of the lens moving device of the present embodiment configured as described above will be described below. FIG. 5 shows the cam plate 31 and the first lens moving frame 3 in the wide angle of the zooming operation.
7, a plan view showing the positional relationship of the second lens moving frame 38,
FIG. 6 shows the cam plate 31 in the telephoto zooming operation,
FIG. 6 is a plan view showing a positional relationship between a first lens moving frame 37 and a second lens moving frame 38. In FIG. 5, in the first lens moving frame 37, the guide pole 42 is inserted into the hole 37a, and the notch portion (not shown) for preventing rotation is engaged with the guide pole 43 to move in the optical axis direction. It is movably supported. Similarly, the second lens moving frame 38 also has a hole 38.
The guide pole 43 is inserted through a, and the guide pole 42 is supported so as to be movable in the optical axis direction by engaging a rotation preventing notch (not shown). Cam plate 31
A pin 60 planted in the first lens moving frame 37 is engaged with the groove 32 formed on the first lens moving frame 37. In addition, the cam groove 33 has a second
The cam follower 61 planted in the lens moving frame 38 is engaged. In FIG. 5, when the rotation of the zoom motor is transmitted to the internal gear integrally formed on the lower surface of the cam plate 31 through the belt and the gear train, the cam plate 31 causes the shaft 47 to rotate about an arrow 62. Rotate in the direction of. And groove 3
Since the pin 60 engaged with 2 and the cam follower 61 engaged with the cam groove 33 are driven in the optical axis direction, the first lens moving frame 37 and the second lens moving frame 38 respectively move in the optical axis direction. Thus, zooming is performed and the camera moves to the telephoto position shown in FIG.

EFFECTS OF THE INVENTION As is apparent from the above description, according to the present invention, a cam having a rotational movement in a plane parallel to the optical axis and a motor having a rotational axis parallel to the rotational axis of the cam are provided. Since it is composed of a transmission means for transmitting the rotation of the motor to the cam via the belt, it is possible to realize low noise, and the wrap angle of the belt can be determined regardless of the optical path diameter, Therefore, there is an excellent effect that efficient belt transmission can be realized. Further, in such a configuration, the pulley diameter can be made smaller than the optical path diameter, and an effect that a lens moving device having a small diameter can be realized can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a conventional zoom lens barrel using a belt, FIG. 2 is a perspective view of a main part of a lens moving device according to an embodiment of the present invention, and FIG. 3 shows a transmission means of the device. FIG. 4 is a sectional view of the same, FIG. 4 is a sectional view thereof, FIG. 5 is a plan view showing the positional relationship between the cam plate and the first and second lens moving frames at a wide angle in the zooming operation, and FIG. 6 is a telephoto of the zooming operation. FIG. 6 is a plan view showing a positional relationship between a cam plate and first and second lens moving frames. 30 ... Lens substrate, 31 ... Cam plate, 32 ... Groove, 3
3 ... Cam groove, 37 ... First lens moving frame, 38 ...
Second lens moving frame, 31a, 51, 52, 54 ... Gear, 56 ... Belt, 59 ... Zoom motor.

Front Page Continuation (72) Inventor Jiro Kajino 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP 58-111003 (JP, A) U) Actually open 52-130740 (JP, U) Actually open 49-73433 (JP, U) Japanese public Sho 49-17369 (JP, B1) Japanese public Sho 46-33493 (JP, B1) Japanese public Hei 3 -63046 (JP, B2) Actual public 57-9764 (JP, Y1) Actual public 49-12601 (JP, Y1) Actual public 57-51366 (JP, Y1)

Claims (1)

[Claims] 1. A first and second lens moving frame, which is held by two guide poles provided on a lens substrate and is movable in an optical axis direction, and is rotatably supported by the lens substrate. And a cam plate which has cam grooves with which pins provided on the first and second lens moving frames engage, and which is rotated by a drive motor to move the first and second lens moving frames. A lens moving device including a transmission unit including a gear train that transmits the rotation of the drive motor to the cam plate, and a belt that transmits the rotation of the drive motor to the transmission unit.