JPH0122602B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lens drive device for an autofocus camera, and more particularly to a lens drive device that allows light manual operation by separating the drive system except during autofocus.

When adjusting the focus manually in an autofocus camera, the mechanism in which the lens helicoid is rotated to reverse the interlocking system and rotate to the motor is either impossible or extremely difficult to manually adjust. was.

SUMMARY OF THE INVENTION An object of the present invention is to provide a lens driving device for an autofocus camera that allows light manual operation and reliable focus adjustment.

In order to achieve the above object, an autofocus camera lens drive device according to the present invention switches and connects the rotation of a motor in a first direction to move an objective lens forward and backward.
a driving gear to which rotation of the motor in a first direction is transmitted; first and second swinging levers that are alternately swung by the rotation of the motor; and a driving gear that is supported coaxially with each of the swinging levers. first and second transmission gears coupled to the gear; first and second transmission gears provided on the first and second swing levers and coupled to the first and second transmission gears; and a lens drive gear that is connectable to the first and second partially toothed gears and transmits their respective rotations to the lens operating mechanism; first and second electromagnetic devices for biasing the second partially toothed gear in a direction to couple with the lens drive gear; and a drive circuit that drives the first and second electromagnetic devices in accordance with a focus adjustment signal. and when the first electromagnetic device is energized, the lens is intermittently driven in a first direction via the first partially toothed gear;
When the second electromagnetic device is energized, the lens is intermittently driven in the second direction via the second partially toothed gear.

According to the above configuration, the object of the present invention can be completely achieved.

The configuration of the present invention will be explained in more detail below with reference to the drawings and the like.

FIG. 1 is a mechanical diagram showing an embodiment of the lens driving device of the present invention.

The drive motor 1 is a dual-purpose motor that operates other mechanisms such as an autowinder. The motor 1 is provided with a small gear 2, and a gear 3 connected thereto meshes with a gear 4. A protrusion 14 is provided on the shaft of the gear 4. The gear 4 meshes with a gear 5 and a gear 6, and first and second swing levers 12 and 13 are swingably provided on shafts 10 and 11 of the gears 5 and 6, respectively. These first and second swing levers 1
Gears 7 and 8 that mesh with gears 5 and 6, respectively, are provided on 2 and 13, and each sandwich gear 9 and provide rotation in opposite directions. Each half has missing teeth.

Furthermore, since gear 4 and gears 7 and 8 have the same number of teeth, they rotate synchronously.

The springs 15 and 16 are provided closer to the gears 7 and 8 than the first and second shafts 10 and 11 of the first and second swing levers 12 and 13, so that the gears 7 and 8 mesh with the gear 9. The first and second swing levers 12 and 13 are biased in directions that do not match. 1st
First and second support members 21 and 23 are disposed on the other end sides of the second swing levers 12 and 13, respectively.
1 and 23, respectively. The first and second springs 22, 24 are connected to the first and second supporting members 21, 23, and the first and second iron pieces 19, 20 provided thereon are connected to the first and second electromagnets 17, respectively. , 18 with a force weaker than that of the first and second springs 15 and 16. The gear 9 is connected to a gear 27 and meshes with a helicoid gear 29 via a gear 28.

Next, the operation of the embodiment of the present invention will be explained with reference to FIGS. 1 and 2.

When the focus is not adjusted automatically, the focus adjustment signal does not come, so the first and second electromagnets 17 and 18
are not energized, and the rotation of the motor 1 in the counterclockwise direction in FIG. 1 is transmitted to the gears 3 and 4 in the directions of the arrows, respectively. The rotation transmitted to the gear 4 gives a counterclockwise rotation to the gear 9 following the gears 5 and 7 on the one hand, and on the other hand, gives a clockwise rotation to the gear 9 from the gears 6 and 8.

However, when the protrusion 14 is on the first swing lever 12 side as shown in FIG. However, at that time, the toothless portion of gear 7 corresponds, so that it does not mesh with gear 9. on the other hand,
Since the second swing lever 13 is not pressed by the protrusion 14, the biasing force of the second spring 16 causes the gear 8 to
is moved away from gear 9, and in that case, even though the toothed parts of gear 8 correspond, gear 9
It doesn't mesh with that.

Then, as shown in FIG. 2, when the protrusion 14 further rotates and advances 180 degrees, the protrusion 14 moves to the second
The second swing lever 13 moves the gear 8 closer to the gear 9 against the second spring 16, and the gear 8 is about to become engaged. enters the missing tooth portion and cannot actually mesh with the gear 9.

In this way, the first and second swing levers 1
2 and 13 shifted their positions by about 180 degrees, and moved gear 4 to 1.
Although periodic rocking corresponding to the rotation is repeated, the rotation of the motor 1 is interrupted between the gears 7 and 8 and the gear 9, and is not transmitted to the helicoid gear 29.

In other words, the motor drive mechanism and the lens helicoid drive mechanism are separated except during automatic focus adjustment.

Next, the operation of the embodiment of the present invention during automatic focus adjustment will be explained using FIGS. 3 and 4.

FIG. 3 is a mechanical diagram showing a state in which the second electromagnet of the embodiment of the lens driving device of the present invention is energized. FIG. 4 is a graph showing focus adjustment over time, with a indicating adjustment toward infinity and b indicating adjustment toward close distance.

When a focusing point adjustment signal is generated in an electric circuit (not shown), a selection is made between adjustment in the infinity direction (first direction) or adjustment in the closest direction (second direction), and the first and second adjustment signals are selected. Either electromagnet 17,1
Current flows through 8. Now, when adjustment is required in the close direction and the helicoid position is at B in Figure 4,
When the current for close direction adjustment flows through the second electromagnet 18 at time Tb, the second iron piece 20 approaches the second electromagnet 18 in conjunction with the reciprocating movement of the second swinging lever 13, and when it comes into contact with it. (See the state in Figure 2) and hold it as it is. Then, after the protrusion 14 has passed the second swing lever 13 (see the state in FIG. 3), the second swing lever 13
6 prevents the restoring force of the second spring 16, and the gears 8 and 9 are maintained in a normal meshing axis. Therefore, the toothed portion of the gear 8 meshes with the gear 9, and the gear 8 rotates the gear 9 in the direction of the arrow in FIG.
Rotate 9 to move the lens in the direction of the arrow.

When the gear 8 rotates once, the missing teeth of the gear 8 cannot drive the gear 9, and when the gear 9 is not driven, an electric circuit (not shown) makes a focus judgment, and as shown in FIG. 4, the gear 9 is intermittently focused. It will move closer to the focal position F.

At the time of focusing Tf, a focusing point judgment circuit (not shown) uses a focusing signal to cut off the current of the second electromagnet 18, so that the second electromagnet 18 releases the second iron piece 20 held therein. When the second iron piece 20 is released, the second spring 16 biases the second rocking lever 13 and pulls the gear 8 away from the gear 9, causing the motor 1 to rotate to uncouple the lens drive mechanism. However, the lens remains at the in-focus position. Conversely, when adjusting toward infinity, the first electromagnet 17 is energized, the gear 7 is meshed with the gear 9 to rotate in the opposite direction, and the lens is driven in the same way.

As described in detail above, according to the configuration of the present invention, the drive mechanism from the motor can be cut off during manual adjustment in an autofocus camera, so that manual adjustment can be easily performed.

Further, since the drive connection is cut off except during automatic focus adjustment, the motor can be used for tasks other than automatic focus, such as automatic winding and mirror drive. Conversely, it has become possible to use the motor of a camera built into a winder to drive automatic focus adjustment.

In addition, the mechanism allows the lens to be adjusted in both directions (close-up adjustment direction and infinity adjustment direction) by rotating the motor in one direction.The lens drive moves intermittently and the motor drive system can be shut off when the focus is focused. Errors in the stopping position due to the inertia of the members interlocked with this are reduced, making it possible to adjust the focal point with extremely high precision.

[Brief explanation of drawings]

FIG. 1 is a mechanical diagram showing an embodiment of the lens driving device of the present invention, FIG. 2 is a mechanical diagram showing a state with a phase opposite to that of FIG. 1, and FIG. 3 is a mechanical diagram showing an embodiment of the lens driving device of the present invention. FIG. 4 is a mechanical diagram showing a state in which the electromagnetic device No. 2 is energized, and FIG. 4 is a graph showing focus adjustment over time. 1... Motor, 2... Small gear, 3, 4, 5,
6, 7, 8, 9...Gear, 10,11...Shaft, 1
2, 13... Swinging lever, 14... Protrusion, 15,
16...Spring, 17,18...Electromagnet, 19,2
0... Iron piece, 21, 23... Supporting member, 22, 2
4...Spring, 25, 26...Protrusion.

Claims (1)

[Claims] 1. In a lens drive device for an autofocus camera that moves an objective lens forward or backward by switching and connecting the rotation of a motor in a first direction, a drive gear to which rotation of the motor in the first direction is transmitted; first and second swing levers that are alternately swung; first and second transmission gears that are supported coaxially with each of the swing levers and coupled to the drive gear; and can be coupled to first and second partially toothed gears provided on a second swing lever and connected to the first and second transmission gears, and to the first and second partially partially toothed gears; a lens drive gear that transmits the respective rotations to the lens operation mechanism; and a lens drive gear that biases the first and second levers in a direction in which the first and second partially toothed gears are coupled to the lens drive gear. a drive circuit that drives the first and second electromagnetic devices according to a focusing signal, and when the first electromagnetic device is energized, the first electromagnetic device The lens is intermittently driven in the first direction via the partially toothed gear, and when the second electromagnetic device is energized, the lens is intermittently driven in the second direction via the second partially toothed gear. A lens driving device for an autofocus camera, characterized in that the lens driving device is configured to be driven in the direction of.