JPS6345563B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lens barrel, and more particularly to a lens barrel that allows manual focusing and automatic focusing.

Various types of automatic focusing devices have been recently developed in the field of photographic optics, and some of them are actually installed in products and put into practical use. However, the currently proposed automatic focusing devices have certain limitations on their operating range, and the problem is that the focusing mechanism cannot operate with a certain degree of accuracy for subjects at close distances. It has points. Therefore, in order to move the photographing lens forward and backward in the optical axis direction and obtain a focused state over its entire operating range, a configuration is required that can selectively perform manual focusing operation and automatic focusing operation.

In addition, the automatic focusing device converts the subject brightness information and subject light into electrical signals, processes the converted electrical signals electrically and logically, calculates the subject distance to the in-focus position, and moves the photographing lens to that distance. Alternatively, by moving the photographic lens and inputting light from the subject, the momentary subject distance is electrically detected, and a focus signal (electrical signal) is generated at the in-focus position.
is now output. Therefore, no matter which type of automatic focusing device is employed, a power source is required as a driving energy source. Therefore, if the power source energy is consumed and is not replenished, this type of automatic focusing device will become inoperable. Therefore, it is necessary to incorporate a manual focusing operation mechanism into the lens barrel and to enable selection and switching between automatic focusing operation and manual focusing operation.

An object of the present invention is to provide a lens barrel capable of selectively switching between manual focusing operation and automatic focusing operation as described above.

An embodiment of the present invention will be explained below with reference to FIGS. 1 to 3. As a means for controlling the movement of the lens holding member by automatic focusing operation, a drive consisting of a motor, a gear train mechanism, etc. There is a force transmitting means, and the transmitting means may be placed on the camera side or on the lens barrel side, especially on the interchangeable lens barrel side, but in this example, the transmitting means is provided on the camera side. Let's discuss an example.

In Fig. 1, an automatic focusing device and a driving device driven by the output of the automatic focusing device are arranged inside the camera body side C, and the output of the driving device operates an interlocking member in the lens barrel L to focus the optical system. An example of operating the system will be shown.

In the figure, the lens barrel L is shown as an interchangeable lens barrel that can be attached to and detached from the camera body C.

Reference numeral 1 indicates the photographic lenses L ₁ to _{L 3} in the lens barrel L.
It is a semi-transparent mirror for guiding the subject light 2 that has passed through it to the finder optical path, and is supported rotatably about an axis 1a. The finder optical path has a known configuration including a condenser lens 3, a pentaprism 4, an eyepiece lens 5, and the like. Reference numeral 6 denotes a sub-mirror held by the mirror 1, which guides a part of the subject light that has passed through the mirror 1 to a line sensor 7 and a focus detection device 8. Reference numerals 7 and 8 relate to a focus detection device using one or more photo sensor arrays, in which an image of an object formed by an imaging lens is detected by a plurality of charge accumulation type or charge accumulation and discharge type photo sensors. received by a photo sensor array consisting of
At this time, by extracting the output of each photo sensor in time series, the object image is electrically scanned, and the scanning output at this time is appropriately processed to perform focus detection. A detection device, and
Other suitable known focus detection devices may also be used.

Reference numeral 9 denotes a drive means, for example, a motor, whose power supply is controlled by a switch means 10, which will be described later.
a, 11b are transmitted to the driving member. The long grooves 12a ₁ , 12a ₂ and pins 12b ₁ , 12b ₂ of the member 12 are means for holding the drive member 12 in a fixed direction.

The pawl gear 13 has a tooth portion 13a that can mesh with a part of the gear train 11a, 11b, and a rotation blocking operation is performed by a movable pawl 14a of an electromagnetic means 14 whose operation is controlled by a signal from the detection device 8. It is done.

Reference numeral 15 designates a release button on the camera body, and when the button 15 is pressed, a switch 16 is closed and power is supplied to the detection device 8, drive means 9, electromagnetic means 14, etc. Reference numeral 17 indicates manual focusing operation means on the lens side, such as selection of the operating scale of the focus adjustment ring fitted on the outermost side of the lens barrel (manual focusing operation...this is represented by the symbol MF, automatic focusing operation...this). (represented by the symbol AF) is a signal pin that is pressed by the selection pin 18 that protrudes and exits toward the camera, and this signal pin 17
The switch 10 is opened and closed by the pressing operation. The selection pin 18 is operated to protrude and retract from the lens barrel toward the camera side by switching between a manual focusing operation and an automatic focusing operation using a manual focusing operation member 20 of the lens barrel L, which will be described later.

2 and 3 show the internal structure of the lens barrel L, and the illustrated state shows the case where the focusing operation member 20 is set in an automatic focusing device.

Reference numeral 21 indicates the base barrel (or fixed barrel) of the lens barrel L, and one end side of the base barrel 21 is provided with coupling means for coupling the lens and camera, such as a bayonet mount ring 22, as shown in FIG. It can be combined with the camera-side mount ring 19 shown in FIG.

Reference numeral 23 denotes an interlocking member which is rotated around the optical axis by the drive member 12 on the camera side when automatic focusing mode is selected, and is smoothly rotated by a ball bearing 24 inside the base tube 21. Retained. The driving member 12 is connected to one end of the interlocking member 23.
It has an engaging element 23a that engages with the engaging part of. 25
is a lens holding member that holds the focusing optical system _L1 and is fitted into the base tube or the interlocking member 23.

26 is the interlocking member 2 that is activated by selecting the manual focusing operation mode or the automatic focusing mode of the focusing operation member 20.
3 is an intermediate member for engaging and disengaging the lens holding member 25 in a connection relationship, and the intermediate member 26
is fixed to the focusing operation member 20 by a screw 27, and is configured to be rotatable on the outer periphery of the base cylinder 21 integrally with the operation member when a focusing operation is performed.

The intermediate member 26 is placed over the outer periphery of the base barrel 21, and is connected to the stepped portion 20a of the rear end (end in the camera mounting direction) of the focusing operation member 20 and the abutting portion 2 of the base barrel 21.
1a is fixed by a restraining ring 28 so as to prevent displacement in the optical axis direction, and is configured to be rotatable on the outer periphery of the base tube 21.

29 is a locking member for fixing the focusing operation member 20 to the base tube 21 during automatic focusing operation, and the locking member 29 passes through the hole 20b of the focusing operation member;
The tip 29a is bent into an L-shape and biased outward by a coil spring 30. The abutting portion 21a of the base barrel 21 with the focusing operation member has an engraved portion on its outer circumferential surface 21b with a scale display, and a triangular mark ▲ as an index for setting the focusing operation member 20 in automatic focusing mode. AF characters are displayed.

The bent end portion 29a of the locking member 29 has a spring 3 attached to the inner peripheral surface of the flange portion 21c formed on the base cylinder 21.
When the focusing operation member 20 is rotated and set at the AF position, the bent portion 29a engages with the notch 21b provided in the flange portion 21c to focus. Rotating operation of the operating member 20 is prevented.

Reference numeral 31 designates an engaging pin that is set up on the lens holding member 25, and the engaging pin 31 passes through the groove 23b provided in the interlocking member 23 and the groove 21e provided in the base tube 21, and further extends into the intermediate member 26. It engages with the provided groove 26a. The groove 23b of the interlocking member 23 continuously forms a groove 23b ₁ in the direction parallel to the optical axis, a groove 23b ₂ in the circumferential direction, and an inclined groove 23b ₃ having a lead in the direction of the optical axis. The groove 26a of the intermediate member 26 is an inclined groove 2 having a lead in the optical axis direction.
6a ₁ , a circumferential groove 26a ₂ , and a groove 26a ₃ parallel to the optical axis are formed continuously as shown.

32 is an engagement pin for keeping the interlocking member 23 in an inoperative state when the manual focus operation member 20 is installed at the manual focus operation position;
2 engages with the linear groove 23c formed in the interlocking member 23 and the grooves 21f ₁ and 21f ₂ formed in the base cylinder 21, and is further fitted into the groove 26c formed in the intermediate member 26. In the lens barrel L having the above configuration, the intermediate member 26 is constructed as a separate component from the manual focusing operation member 20, but the grooves 26a ₁ , 26a ₂ , 26a ₃ , 26c and the tapered portion 26b of the intermediate member 26 may be formed on the inner peripheral surface side of the focusing operation member 20.

The operation and operation of the camera and lens barrel shown in the embodiment shown in FIGS. 1 to 3 will be described.

When the focusing operation member 20 of the lens L and the ▲ mark on the base barrel 21 are aligned to set the AF mode, the selection pin 18 is projected toward the camera against the spring 33 by the tapered portion 26b of the intermediate member 26, and the selection pin 18 is pressed against the spring 33. The switch 10 on the camera side is closed via the switch 17. When the subject is determined and the release button 15 is pressed, a power supply switch 16 to the automatic focus detection device 8 is closed, and power is supplied to the detection device 8, the electromagnetic means 14, and the motor 9 of the drive means. Electromagnetic means 1
4, the movable pawl 14a of the electromagnetic means is attracted against the force of the spring 14b and disengaged from the gear pawl 13. In this state, light 2 from the subject passes through the photographing lens of lens L, passes through half mirror 1, is reflected by sub mirror 6, and is reflected by line sensor 7.
is input, and the detection device 8 can start calculation for distance measurement of the object distance. The rotation of the motor 9 caused by the release operation causes the drive member to move in the direction of arrow A via the gear trains 11a and 11b. The interlocking member 23 on the lens side connected to the driving member 12 is rotated around the optical axis, and the rotational force of the interlocking member 23 is applied to the engagement pin 31 set on the lens holding member 25.
The lens holding member 25 is moved in the optical axis direction by the engagement relationship between the inclined groove _23b3 of the interlocking member 23, the straight groove 21c of the base tube 21, and the straight groove _26a3 of the intermediate member 26. By this movement in the optical axis direction of 25, the photographing lens moves from the initial position (for example, infinity position) to the close position, and inputs light from the subject to the line sensor 7 through the camera's mirror 1 and sub-mirror 6. The line sensor 7 and the detection device 8 sequentially output signals corresponding to the object distance, and when the photographic lens comes to the in-focus position, the detection device 8 outputs a focus signal. The power supply to the electromagnetic means is stopped by this focusing signal, and the attractive force of the movable claw 14a disappears.
The movable pawl 14a locks the pawl gear 13 by the spring 14b, and the operations of the gear train 11a, 11b, the driving member 12, and the interlocking member 23 are stopped. While maintaining this automatic focusing state, the camera and lens perform exposure control operations by moving mirror 1 to the dotted line position and operating a shutter device and aperture device (not shown).

Starting with the operation of the release button 15 explained above, the operation of the camera's automatic focus detection control circuit 8 - the operation of the lens barrel L - the operation of the camera's exposure control mechanism - When the cycle is completed, the lens barrel L
The interlocking member 23 returns to the predetermined initial position. As means for returning the interlocking member 23 to its initial position, a motor reversal control circuit (not shown) that is activated by the movement of the rear curtain member 34 of the shutter device is connected to the motor 9 of the drive means, and the movement of the rear curtain member 34 of the shutter device connects the motor reversal control circuit (not shown) to the motor 9 of the drive means. Then rotate the motor 9 in the reverse direction and drive the drive member 1.
2 may be moved in the direction opposite to the arrow A to return the interlocking member 23 to its initial position.

Next, a case will be described in which the automatic focusing operation is switched to the manual focusing operation.

When switching from automatic focusing operation to manual focusing operation as shown in FIG. 2 and FIG. When the lock member 29 is rotated in the opposite direction of arrow B, the engagement between the bent portion 29a of the locking member 29 and the cutout portion 21d of the base tube is released, and the bent portion 29a is brought into contact with the lower surface (inner peripheral surface) of the flange portion 21c of the base tube. It slides into contact and rotates. By this rotational operation of the manual focusing operation member, the interlocking member 23 is displaced from the operating region to the stopped or stationary region. That is, as the operating member 20 is rotated, the intermediate member 26 is also rotated in the same direction. At this time, the engagement pin 32 is connected to the intermediate member 2.
In order to contact and be pushed by the tapered surface _26c1 of the displacement groove 26c of No. 6 and rotate in the same direction, the engagement position with the groove of the base cylinder of the engagement pin 2 is a groove 21f formed in the circumferential direction. Straight groove 2 formed from ₁ in a direction parallel to the optical axis
Move to 1f ₂ . Furthermore, by switching and rotating the operating member 20, the engagement pin 31 and the groove 26a of the intermediate member are
In the engagement relationship, the groove is displaced from the straight groove 26a ₃ to the inclined groove 26a ₁ via the circumferential groove 26a ₂ , and further,
In the engagement relationship with the groove 23b of the interlocking member 23, the straight groove ₂ passes from the inclined groove _23b3 to the circumferential groove 23b2.
3b ₁ is displaced. When a focusing operation is performed using the focusing operation member 20 in this state, the lens holding member 25 is moved between the engagement pin 31 and the rectilinear groove 21e of the base barrel.
Due to the engagement relationship between the inclined grooves 26a ₁ of the intermediate member 26, it moves in the optical axis direction according to the lead angle of the inclined grooves 26a ₁ . In this case, the rotation of the interlocking member 23 is restricted because the engagement pin 2 engages with the linear groove 21f ₂ of the base barrel, and the width of the groove 23b ₁ is such that the engagement pin 1 is The dimensions should be large enough to allow rotation in the circumferential direction around the optical axis.

The selection pin 18 opens and closes the switch 10 on the camera side by moving forward and backward in a direction parallel to the optical axis using a switching tapered surface 26b formed on the end surface of the intermediate member 26 during switching operation of the manual focusing operation member. It will be done. Incidentally, as described above, the opening/closing operation of the switch 10 can be performed as a separate and independent opening/closing operation of the switch 10 without being linked to the switching operation of the lens barrel from the automatic focusing mode to the manual focusing mode. Good too.

FIG. 4 shows another embodiment of the lens barrel and camera of the present invention, and particularly shows an example in which a drive mechanism for driving the lens holding member 39 is built into the lens barrel. In the drawings, parts having the same functions as those in FIGS. 1 to 3 are indicated by the same reference numerals. In this embodiment, a motor drive means 9, a gear 11a, a pawl gear 13, and an electromagnetic means 14 are arranged inside the lens barrel, and electric signal contacts 40a, b,
41a and 41b are configured to be energized and controlled.

The example of the configuration shown in FIG. 4 is substantially the same as the example of the configuration shown in FIG. 1, except that the driving force transmission mechanism is incorporated into the camera side. The structure of the lens barrel shown in Figures 2 and 3 is the lens that constitutes the lens optical system.
Although the case of a lens optical system that obtains focusing by moving part of the lens L ₁ out of L ₁ , ₂ , and L ₃ has been illustrated, a lens barrel to which the present invention is applied is as shown in FIG. The present invention is also applicable to a configuration in which the entire lens optical system is moved. In other words, when the entire lens is extended as shown in Figure 5, the lens
L ₄ and L ₅ may be fixed to the lens holding member 43.

As described above, according to the present invention, it is possible to easily switch to the automatic focusing state by rotating the focusing operation member for manual focusing operation, and therefore the object brightness information can be obtained in the automatic focusing state. When distance measurement becomes impossible due to insufficient distance measurement, the focus operation member can be rotated to switch to manual mode, and the focus can be adjusted manually with the same operation, providing extremely good operability. or,
In the present invention, when switching to the automatic focusing state, the focusing operation member can be kept in a fixed state even while moving the focusing lens, and the camera and the camera during shooting can be kept in a fixed state.
Holding the lens becomes easier, and mistakes such as unexpected failures due to rotation of the focusing operation member can be avoided.

[Brief explanation of drawings]

FIG. 1 is a sectional view of essential parts showing a specific example of a camera that can be applied to the lens barrel according to the present invention. FIGS. 2 and 3 show an embodiment of the present invention as an interchangeable lens, with FIG. 2 being an axial sectional view and FIG. 3 being a developed view of the main parts. FIG. 4 is an explanatory diagram of a case where a drive system is disposed within the lens barrel when the lens barrel of the present invention is operated in automatic focusing mode. FIG. 5 shows an axial cross-sectional view of the present invention in which the photographing lens is an optical system whose entire length is extended. C... Camera, L... Lens barrel, 20... Manual focusing operation member, 23... Interlocking member, 25, 43
... Lens holding member, 26 ... Intermediate member.

Claims (1)

[Claims] 1 An intermediate member that rotates around the optical axis is arranged on the outer diameter side of the fixed base tube, and an interlocking member that rotates around the optical axis is arranged on the inner diameter side, and focus adjustment is performed on the inner diameter side of the interlocking member. A lens holding member that holds a lens for use and moves in the optical axis direction is arranged, and a focusing operation member that rotates around the optical axis and the intermediate member are connected so as to interlock around the optical axis. The movement of the motor based on the focusing device and the interlocking member are connected so as to interlock around the optical axis, and the intermediate member further has a lead amount for moving the lens holding member in the optical axis direction. A first inclined groove and a first linear groove extending in the optical axis direction are provided so as to be continuous in a first communication groove parallel to the optical axis, and the base barrel has a linear groove extending in the optical axis direction. the interlocking member has the first inclined groove and the first inclined groove.
A second inclined groove having a lead amount for moving the lens holding member in the optical axis direction and a second groove extending in the optical axis direction so as to be opposite to the straight groove in the direction around the optical axis. The second groove is parallel to the optical axis.
The lens holding member further includes the intermediate member,
An engaging pin that engages with each of the grooves of the base tube and the interlocking member is provided, and the intermediate member is rotated around the optical axis so that the engaging pin engages with the first linear groove of the intermediate member. The automatic focusing device is enabled when the engagement pin is located in the first inclined groove and in the second inclined groove of the interlocking member, and conversely, when the engagement pin is located in the first inclined groove and 1. A lens barrel capable of automatic focusing, characterized in that a switch means is provided for deactivating the automatic focusing device when the automatic focusing device is located in the straight groove of the lens barrel.