JP2563056Y2 - Lens barrel with automatic and manual focus adjustment - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a manual focusing (hereinafter referred to as M
F) and a lens barrel capable of automatic focusing (hereinafter referred to as AF).

[0002]

2. Description of the Related Art The following lens barrels have been proposed by the present applicant. It receives the power supply from the AF camera body side and drives the motor of the focusing optical system for AF, and switches the AF or MF focus mode by a clutch using a motor or a solenoid. By operating the operation ring, it is possible to switch to MF at any time without any special switching operation. In this way, normal photographing is performed by AF, and in photographing of a subject that is difficult to focus or blurring intentionally, switching to MF can be performed smoothly by operating the distance operation ring.

[0003]

In the prior art described above, when switching from the MF mode to the AF mode, the clutch means moves in the optical axis direction if the distance operation ring is kept in a state where a force is applied in the rotational direction. In such a case, friction occurs at the connecting portion between the distance operating ring and the clutch means, and there is a risk that the clutch may not be switched due to the frictional force depending on the amount of electric force driving the clutch means.

The present invention has been made in view of the above-mentioned problems, and has as its object to provide a lens barrel that solves the above-mentioned disadvantages.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a focusing optical system (L2); and is rotatable around an optical axis. Moving means (4) for moving the moving means in the optical axis direction; operating means (13) capable of rotating around the optical axis and driving the moving means by the operation; Motor means (15); selection means (11) for selectively selecting one of an automatic focus adjustment mode and a manual focus adjustment mode
3) and; a first connecting the moving means and the electric means.
And a clutch means (8) which can be electrically displaced along the optical axis direction to a position of the second position and a second position for releasing the connection and connecting the moving means and the operating means, respectively; When the automatic focus adjustment mode is selected, the clutch means is displaced to the first position, and when the manual focus adjustment mode is selected by the selection means, the clutch means is displaced to the second position. Connecting means (21) for radially connecting the moving means and the operating means with the displacement of the clutch means from the first position to the second position. Is provided.

[0006]

According to the lens barrel of the present invention, when switching from the MF mode to the AF mode, the operation means (distance operation ring)
Even if is kept in a state where a force is applied in the rotational direction, the amount of the force does not generate a frictional force on the clutch means, so that the clutch can be switched smoothly.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of an embodiment of a lens barrel according to the present invention. FIGS. 2, 3, and 4 are manuals using a bistable solenoid (hereinafter, simply referred to as a solenoid) in the embodiment. FIG. 2 is a structural view (a view A in FIG. 1) of a focus (hereinafter, referred to as MF) -autofocus (hereinafter, referred to as AF) switching clutch. FIG. 2 is an MF state, FIG. 3 is an AF state, and FIG. 13 shows the shapes of the engagement portions. FIG. 5 shows AF, MF and MF priority AF with the lens barrel according to the present invention mounted on the camera body.
FIG. 2 is an operation schematic diagram for explaining the operation of FIG.

In FIG. 1, a fixed cylinder 1 having a bayonet claw 1a for mounting on a camera body is composed of an outer cylinder 1b and an inner cylinder 1c, and an inner periphery of the inner cylinder 1c has
The imaging optical systems L1 and L3 are held, and the lens holding cylinder 2 that holds the focusing optical system L2 is slidably provided. A pin 3 is provided on the holding cylinder 2, and the pin 3 is provided on a rotating cylinder 4 rotatably fitted on a straight guide groove 1 d provided on the inner cylinder 1 c and on the outer periphery of the inner cylinder 1 c. Lead groove 4a
And the rotating barrel 4 rotates, so that the focusing optical system L
2 is moved in the optical axis direction to perform a focusing operation.

The rotating cylinder 4 has a circumferential groove 4 provided in the rotating cylinder 4.
The movement in the optical axis direction is restricted by b and the pin 5 fitted on the fixed cylinder 1 and fitted thereto, and the rotation around the optical axis is also restricted with a fixed rotation angle. On the other hand, a pattern section 6 of the encoder is provided on the front side of the rotating cylinder 4. A detection unit 7 for the pattern 6 of the encoder is provided in the inner cylinder 1c, and a signal such as a rotation direction and a rotation angle of the rotating cylinder 4 is sent to a CPU (corresponding to 110 in FIG. 4) inside an interchangeable lens (not shown). It is configured to transmit to.

A motor 15 is provided in the inner cylinder portion 1c of the fixed cylinder 1, and its rotation is transmitted to the segment gear 14 by a gear train (not shown). A distance operation ring 13 operable from the outside is rotatably fitted on the outer periphery of the fixed cylinder 1. The distance operation ring 13 is provided with an encoder pattern 16 as rotation detection means, and a detection unit 17 fixed to the fixed cylinder 1 detects a signal such as a rotation direction and a rotation angle of the distance ring 13, This is transmitted to the CPU inside the lens barrel (not shown).

Next, the structure of an MF-AF switching clutch using a bistable solenoid will be described with reference to FIGS. A solenoid 8 is provided on the outer peripheral side of the rotating cylinder 4, and its shaft 8 a moves forward and backward in the optical axis direction by an electric signal, and at the same time, the plate 9 in contact with the shaft 8 a also advances and retracts in the optical axis direction. It is provided to move.

On the other hand, the shafts 12a and 12b are held by the plate member 9 and the plate member 10 provided integrally with the rotary cylinder 4, and are in contact with the intermediate portions 12c and 12d of the shafts 12a and 12b. The bent portions 9b and 9c of the plate member 9 are provided so as to be movable forward and backward in the optical axis direction in conjunction with the shaft 8a. Holes 4e and 4f are provided in the protruding portions 4c and 4d of the rotating cylinder 4, and the shafts 12a and 12b are fitted to the holes 4e and 4f, respectively.

Further, a connecting member 21 is mounted on the protruding portion 4c so as to be rotatable about a mounting shaft 21a. A distance operation ring is provided on the front side (upward in FIG. 2) of the connecting member 21.
A projection 14a of the segment gear 14 is disposed near the projection 13a on the rear side (downward in FIG. 2) of the projection 4d, and the projection 13a is engaged with one end of the connecting member 21. Groove 13
A plurality of elongated holes 14b are provided on the protruding portion 14a in the circumferential direction so as to have the same diameter as the shaft 12b and to fit the shaft 12b.

Then, each of the projections 13a, 4c, 4d, 14a
When the shafts 12a and 12b are in the front position, the shafts 12a and 12b push the end surface of the connecting member 21 upward in the drawing, and
The connecting member 21 rotates about the mounting shaft 21a against a spring (not shown), and one end of the connecting member 21 is radially engaged with the groove 13b of the distance operating ring 13. The shaft 12b is a hole in the segment gear 14.
14b does not fit (FIG. 2).

On the other hand, when the shafts 12a and 12b are at the rear positions, the shaft 12b is simultaneously fitted into the hole 4f of the rotary cylinder 4 and the hole 14b of the segment gear 14. Also, the connecting member 21 is rotated in the radial direction by a spring (not shown) so that the shaft 12a is disengaged from the groove 13b of the distance operation ring 13 due to the rearward movement of the shaft 12a,
The groove 13b of the distance operation ring 13 is not engaged (FIG. 3). As shown in FIG. 4, the groove 13 b is formed in a trapezoidal shape so that when the rotational force of the distance operating ring 13 is applied, the component force is applied in a direction of releasing the engagement with the connecting member 21. The leaf spring 11 when the shaft 12a is on the front side
The urging force of the contact portion 11a is set to be larger than the combined force of the amount of force of a spring (not shown) of the connecting member 21 and the above-described component force of the distance operation ring 13.

When the shafts 12a and 12b are at the front position,
The distance operation ring 13 and the rotary cylinder 4 are integrally rotatable, and when in the rear position, the segment gear 14 and the rotary cylinder 4 are integrally rotatable. Also, axis 12
a and 12b are contact portions 11a of the leaf spring 11 provided on the plate material 9;
By 11b, the shaft 12a is urged forward, the shaft 12b is urged rearward, and the connecting member 21 is urged by a spring (not shown) in a direction in which the engagement with the groove 13b is released. Since the biasing force of the shaft 12a is set to be greater than the biasing force of the connecting member 21, the fitting to the grooves 13b and 14b when the shafts 12a and 12b move forward and backward, respectively, is performed smoothly.

As described above, since a plurality of grooves 13b of the distance control ring 13 and a plurality of holes 14b of the segment gear 14 are provided, the rotary cylinder 4 and any one of the distance control ring 13 and the segment gear 14 are optional. Even if the angular positional relationship of
Thus, smooth connection between the distance operation ring 13 and one of the segment gears 14 is performed. The point which should be noted in this embodiment is as follows. That is, when the shafts 12a and 12b are displaced in the optical axis direction to the front side positions, the distance operation ring 13 and the rotating cylinder 4 are made to be able to rotate integrally.
The connection member 21 for connecting the two is not directly connected to the shaft 12a, and the connection direction is set to the radial direction. With this configuration, even if the distance operation ring 13 remains in a state where a force is applied in the rotational direction, the amount of the force does not generate a frictional force on the shaft 12a, so that the smooth shaft 12a,
12b movement is possible. Therefore, the shafts 12a and 12b can be reliably displaced in any state.

Next, the operation of this embodiment will be described with reference to FIG. 4 which shows a schematic diagram of a system in which a camera and a lens are combined. In the present embodiment, the following three modes are set as the mode switching switch 113 as the shooting modes related to focusing.
Can be selected arbitrarily. Automatic focus adjustment (AF) mode Manual focus adjustment (MF) mode MF priority AF mode Hereinafter, each mode will be described step by step.

Automatic focus adjustment (AF) mode The AF is operated by a mode changeover switch 113 which can be operated from outside.
When the mode is selected, a signal indicating the AF mode is output to the CPU 110 inside the lens, whereby the CPU 110
Operates the solenoid 114 so that the driving force of the motor 112 can be transmitted to the focusing optical system L2.

More specifically, referring to FIG.
The shaft 8a is moved rearward, and accordingly the shafts 12a and 12b also move rearward, so that the rotary cylinder 4 is rotated only by the segment gear 14 rotated by the motor 15 (the state shown in FIG. 3). In FIG. 4, the light beam from the subject passes through the taking lens and passes through the semi-transparent mirror of the camera body 101.
The light reaches 102 and a part of the light flux is reflected to form a subject image on the focusing screen 103. This subject image is a condenser lens 104
, Pentaprism 105 and finder eyepiece 106
To the photographer's eyes via

A part of the light passing through the semi-transparent mirror 102 is
The light is reflected by the sub-mirror 107 and guided to the photoelectric conversion unit 108 for distance measurement. The output signal from the photoelectric conversion unit 108 is input to a well-known focusing control circuit 109, which determines the driving direction and the driving amount of the focusing optical system L2. These drive signals are transmitted to the CPU 110 inside the lens, and from there, the motor 112 (corresponding to 15 in FIG. 1) via the motor drive circuit 111.
And drive is performed until the drive amount is reached. When the driving is completed, the in-focus state is detected again. If the in-focus state is not achieved, the above operation is repeated until the in-focus state is achieved.

A limit circuit 117 is provided in the rotation restricting portion of the rotating barrel 4. When the focusing optical system L2 reaches an infinite or close position, a signal is transmitted to the CPU 110 of the lens barrel to focus. The driving direction of the optical system L2 is reversed. As described above, the focusing optical system L2 is driven by the AF, and a focused state for a desired subject can be obtained.

Manual focus adjustment (MF) mode The MF is controlled by a mode changeover switch 113 which can be operated from outside.
When the mode is selected, a signal indicating the MF mode is output to the CPU 110 inside the lens, thereby
Actuates the solenoid 114 so that the rotation of the distance operation ring 115 can be transmitted to the focusing optical system L2.

More specifically, referring to FIG.
The shaft 8a is moved to the front side, and the shafts 12a and 12b are also moved to the front side. Accordingly, the rotary cylinder 4 is rotated only by the distance operation ring 13 (the state shown in FIG. 2). Then, the photographer performs a manual focusing operation by rotating the distance operation ring 13 while looking through the viewfinder eyepiece 106. At this time, the operation of the focus control circuit 109 is prohibited.

As described above, the MF focusing optical system L2
Is performed, and a focused state for a desired subject can be obtained by a manual operation of the photographer. MF priority AF mode MF by mode switch 113 operable from outside
When the priority AF mode is selected, a signal indicating the MF priority AF mode is output to the CPU 110 in the lens, whereby the CPU 110 first operates in the same state as in the AF mode, that is, activates the solenoid 114 to reduce the driving force of the motor 112. The state can be transmitted to the focusing optical system L2.

During the AF operation, M
When the photographer wants to switch to the F mode, the photographer does not use the mode changeover switch 113 but rotates the distance operation ring 115.
When the F operation is performed, the rotation detecting device 116 detects the rotation of the distance operation ring 115 and outputs this to the CPU 110 in the lens as a signal. Upon input of the signal, the CPU 110 immediately activates the solenoid 114, in the same state as in the MF mode, that is, the operation of the focusing control circuit 109 is prohibited, and the distance operation ring 115
Can be transmitted to the focusing optical system L2.
Thus, the photographer can immediately perform the MF operation without the MF-AF switching operation by the mode switch 113.

A method for returning from the MF state to the AF state in the MF priority AF mode is a signal for returning from the MF state to the AF state after a lapse of a predetermined time since the rotation signal of the MF operation ring stops being generated. Is output from the CPU 110 in the lens to actuate the solenoid 114 to operate the clutch mechanism, or a signal by re-pressing the release button of the camera body halfway to the CPU in the lens to actuate the solenoid 114 based on this signal. And a method of operating a clutch mechanism.

[0028]

According to the lens barrel of the present invention, in the MF mode, the MF operation means and the moving means are directly engaged to prevent the clutch means from being disengaged. When the clutch mechanism is moved for switching, even if a rotational force is applied to the MF operation means, the clutch mechanism does not move due to frictional force and switching is not performed, so that switching can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of a lens barrel according to the present invention;

FIG. 2 is a structural diagram (a view A in FIG. 1) of a manual focus / auto focus switching clutch using a bistable solenoid according to the present embodiment, showing a manual focus state;

FIG. 3 is a diagram showing a structure of a manual focus / auto focus switching clutch using a bistable solenoid according to the present embodiment (a view A in FIG. 1) showing an auto focus state;

FIG. 4 is a view showing the shape of a groove provided in a distance operation ring;

FIG. 5 is an operation schematic diagram for explaining operations of auto focus, manual focus, and manual focus priority auto focus by attaching a lens barrel to a camera body.

[Description of Signs of Main Parts]

 DESCRIPTION OF SYMBOLS 1 ... Fixed cylinder L2 ... Focusing lens 4 ... Lens drive member 7, 17 ... Detector 8 ... Bistable solenoid 12 ... Clutch member 13 ... Distance operation ring 14 ... Segment gear 15 ... Motor 18 ... Mode switch 19 ... Cam ring 21 ... Connecting member

Claims (1)

(57) [Scope of request for utility model registration] A focusing optical system; a moving means rotatable about an optical axis, and a moving means for moving the focusing optical system in an optical axis direction by the rotation; and a rotatable operation about the optical axis. An operating means capable of driving the moving means by the operation; an electric means for rotating the moving means; and selectively selecting one of an automatic focus adjustment mode and a manual focus adjustment mode. Possible selecting means; a first position for connecting the moving means and the electric means, and a second position for disconnecting the connecting means and connecting the moving means and the operating means, respectively. Clutch means displaceable along an axial direction; when the automatic focus adjustment mode is selected by the selection means, the clutch means is displaced to the first position; and the manual focus adjustment mode is set by the selection means. When selected And control means for displacing the latch means to said second position; said clutch means said first
And a connecting means for connecting the moving means and the operating means from the radial direction as the lens mirror is displaced from the second position to the second position. Tube.