JPH11211966A - Collapsible mount type zoom lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify structure and to improve operability. SOLUTION: Plural cam projections 21 are formed on the outer peripheral surface of a zoom cam ring and plural cam grooves 61 are formed on the inner peripheral surface thereof. The cam projections 21 of the zoom cam ring are engaged with front and rear cam followers 35 and 37 protrusively provided on the inner peripheral surface of a straight advance ring 31, and an interlocking projection 67 protrusively provided on the outer peripheral surface of a lens holder 65 is engaged with the cam groove 61. The cam projection 21 and the cam groove 61 are formed of zoom cam parts (21a and 61a) and collapsible cam parts (21b and 61b) respectively and consecutively formed on the zoom cam parts (21a and 61a). When the zoom cam ring is turned in a left direction, the ring 31 and the lens holder 65 are driven by the collapsible cam parts (21b and 61b) of the cam projection 21 and the cam groove 61, retreat to a collapsible position S and are in a collapsible state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a retractable zoom lens barrel mounted on a camera or the like, and more particularly to a technique for simplifying the structure and improving operability.

[0002]

2. Description of the Related Art In recent years, some compact cameras having a retractable lens barrel housed in a camera body have emerged in order to improve portability during non-shooting. For example, Japanese Patent Application Laid-Open No. 4-179906 discloses that an intermediate cylinder which is helicoid-coupled inside a fixed cylinder, and a movable cylinder which is helicoid-coupled inside the intermediate cylinder, are driven by rotating the intermediate cylinder. A zoom lens barrel is described in which a movable barrel and a movable barrel protrude and retract from a fixed barrel (that is, a camera body). In this type of lens barrel, the photographer operates the switch as appropriate to rotate the lens motor forward or backward, and the intermediate barrel and the movable barrel are extended from the camera body to be in a shooting posture, or the intermediate barrel and the movable barrel are rotated. It is drawn into the camera body and becomes a transport position.

As described in Japanese Patent Application Laid-Open No. 8-339004, an interchangeable zoom lens barrel mounted on a single-lens reflex camera or the like also has a lens holding mechanism with respect to a fixed barrel mounted on a camera body. It is known to make a cylinder and a collapsible cylinder appear and disappear. In this zoom lens barrel, independently of the photographing cams (zoom cam and focus cam), a retractable cam having a retractable lock groove at the front and rear ends of the rectilinear groove and a lead cam for moving the lens holding barrel and the retractable cylinder forward and backward are provided. It is formed on a fixed cylinder and a retractable cylinder. In this zoom lens barrel, the photographer manually rotates the collapsible barrel, whereby the lens retainer barrel and collapsible barrel are extended from the fixed barrel to take a shooting posture, or the lens retainer barrel and collapsible barrel are fixed. It is drawn into the cylinder to be in a transport position.

[0004]

When the above-mentioned conventional collapsing method is applied to an interchangeable zoom lens barrel, each has a structural or manufacturing problem. For example, in the zoom lens barrel disclosed in Japanese Patent Application Laid-Open No. 4-179906, since the intermediate barrel and the movable barrel are protruded and retracted from the camera body, the interchangeable zoom lens barrel has a restriction on the mounting mount to the camera body. In addition, with a single-lens reflex camera, it is further difficult to prevent interference with the mirrors of the intermediate cylinder and the movable cylinder, and the reality is very poor.

The zoom lens barrel described in Japanese Patent Application Laid-Open No. 8-339004 uses a collapsible cylinder formed with a collapsible cam and a lead cam in addition to a photographing cam. This necessitates the increase in the number of parts and the complexity of the structure. In this publication, reference is made to a technique of providing an extension cam portion for moving the retractable lens group on the zoom cam of the zoom cam ring. In this case, the rotation amount of the zoom cam ring (the rotation angle of zooming) becomes excessively large. It is pointed out that it becomes difficult. The present invention has been made in view of the above circumstances, and has as its object to provide a collapsible zoom lens barrel with a simplified structure and improved operability.

[0006]

According to a first aspect of the present invention, there is provided a fixed cylinder fixed to a mount on a camera side and rotatably engaged with the fixed cylinder. A zoom ring that is restricted from moving in the optical axis direction with respect to the fixed cylinder; and a zoom cam that rotates in conjunction with the zoom ring and is restricted from moving in the optical axis direction with respect to the fixed cylinder. A ring, a cam follower that engages with a cam formed on the zoom cam ring, and a lens group holding member that moves in the optical axis direction with rotation of the zoom cam ring;
The cam includes a zoom cam unit that drives the cam follower to move the lens group holding member in a zoom region, and a zoom cam that drives the cam follower to move the lens group holding member to the mount outside the zoom region. And a collapsible cam portion that is continuous with the zoom ring, and further includes a regulating member that regulates a rotation range of the zoom ring or the zoom cam ring so that the cam follower does not deviate from the zoom cam portion. According to the present invention, when the photographer rotates the zoom ring during photographing,
The cam follower is driven by the zoom cam portion of the zoom cam ring, and the lens group holding member moves forward and backward in the zoom region. Also, when the photographer rotates the zoom ring with the restricting member retracted by the changeover switch or the like, the cam follower is driven by the retractable cam portion of the zoom cam ring, the lens group holding member retreats to the mount side, and the retractable lens is retracted. Done.

According to a second aspect of the present invention, in the retractable lens barrel according to the first aspect, a zoom encoder for detecting a rotational position of the zoom ring in the zoom region, and the zoom ring are outside the zoom region. And a collapsible state detection device for detecting the fact. According to the present invention, when the rotation position of the zoom ring in the zoom region is detected by the zoom encoder, the detection information is output to the camera side, and the control device in the camera performs various calculations and processes. When the retracted state detection device detects that the zoom ring is out of the zoom range, the detection information is output to the camera side, and the control device in the camera performs a process at the time of the retracted state.

According to a third aspect of the present invention, in the retractable lens barrel according to the second aspect, a signal output device for outputting a signal to a control device in the camera, and the zoom ring is outside the zoom region. Further, there is proposed a camera equipped with a collapsed signal output device for outputting a servo drive inhibition signal and a release lock signal to a control device in the camera via the signal output device. According to the present invention, when the retracted state detection device detects that the zoom ring is out of the zoom region, the retracted signal output device outputs a servo drive inhibition signal and a release lock signal to a control device in the camera, and the camera side. To prevent inadvertent operation.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of the zoom lens barrel according to an embodiment of the present invention when photographing, and FIG. 2 is a longitudinal sectional view of the zoom lens barrel when retracted. 1 and 2, a member denoted by reference numeral 1 is a stepped cylindrical fixed mount mounted on a camera (not shown), and a plurality of bayonet lugs 2 are provided on the outer peripheral surface thereof.
Are formed. A fixed cylinder 3 having a cylindrical shape is screwed to a front end of the fixed mount 1. A zoom ring 5 is rotatably supported at the front end of the fixed barrel 3. A guide groove 7 formed on a part of the outer circumferential surface of the fixed barrel 3 and an inner circumferential face of the zoom ring 5 are formed. Engagement with the pin 9 prevents the zoom ring 5 from being detached from the fixed cylinder 3. In the figure, reference numeral L denotes an optical axis that is a center of travel of light from a subject, and a rotating component such as the zoom ring 5 rotates around the optical axis L.

A cylindrical zoom interlocking ring 11 is disposed inside the zoom ring 5, and a rectilinear groove 13 formed in the inner peripheral surface on the distal end side of the zoom ring 5 and a rectilinear motion formed in the zoom interlocking ring 11. The key 15 is engaged. Zoom interlock ring 11
Are integrated with a zoom cam ring 17 and a plurality of bridges 19 disposed inside the lens barrel. Thus, when the photographer rotates the zoom ring 5, the rotational force is transmitted via the zoom interlocking ring 11, and the zoom cam ring 17 also rotates by the same angle.

A plurality of cam projections 21 are formed on the outer peripheral surface of the zoom cam ring 11 as shown by a solid line in a developed view of FIG. A cylindrical rectilinear ring 31 is disposed between the zoom ring 5 and the zoom cam ring 11, and the cam projection 21 of the zoom cam ring 11 includes front and rear cam followers 35, which are provided on the inner peripheral surface of the rectilinear ring 31. 37. In the figure, reference numeral 39 denotes a straight key fixed to the fixed mount 1, which engages with a straight guide groove 41 formed in the straight ring 31;
The rotation of the rectilinear ring 31 is prevented. Thus, when the zoom cam ring 11 (that is, the zoom ring 5) rotates, the rectilinear ring 31 advances and retreats along the optical axis L. In the figure,
Reference numeral 43 denotes a first decorative ring screwed on the outer peripheral surface of the zoom cam ring 11, and includes a zoom ring 5 and a zoom cam ring 11.
And rotate together.

A focus ring 47 for holding a first lens group 45 composed of two lenses is disposed in front of the rectilinear ring 31 and has a helicoid ring 49 fixed to the inner peripheral surface thereof.
Are fitted on the straight running ring 31. A male helicoid screw 51 is formed on the outer peripheral surface of the rectilinear ring 31, while a female helicoid screw 53 is formed on the inner periphery of the helicoid ring 49, and the male helicoid screw 51 and the female helicoid screw 5 are formed.
3 is screwed. Therefore, the focus ring 47
When rotated by a photographer or the like, the device advances and retreats along the optical axis L with respect to the rectilinear ring 31 according to the amount of rotation. In the figure, reference numeral 55 denotes a lens barrel-side coupler driven by a camera-side coupler during autofocusing, and is connected to a sector gear 57 formed on the outer peripheral surface of the focus ring 47 via a gear mechanism (not shown). Reference numeral 59 denotes a second decorative ring, which includes the zoom cam ring 11 and the helicoid ring 49.
And the focus ring 47 and the helicoid ring 4
9 is covered.

On the other hand, a plurality of cam grooves 61 are formed on the inner peripheral surface of the zoom cam ring 11 as shown by broken lines in the developed view of FIG. A lens holder 65 that holds a second lens group 63 composed of four lenses is fitted inside the zoom cam ring 11, and the cam groove 6 of the zoom cam ring 11 is
1 is engaged with an interlocking projection 67 protruding from the outer peripheral surface of the lens holder 65. A guide groove 69 is formed on the outer peripheral surface of the lens holder 65, and a straight-moving interlocking key 71 screwed to the fixed cylinder 3 is engaged with the guide groove 69. As a result, when the zoom cam ring 11 (that is, the zoom ring 5) rotates, the lens holder 65 moves forward and backward along the optical axis L.

As shown in the development of FIG. 3, the cam projection 21 and the cam groove 61 are provided with the zoom cam portions 21a and 61a.
And retractable cam portions 21b and 61b formed continuously with the zoom cam portions 21a and 61a, respectively. In FIG. 3, the zoom cam ring 11 has an angle range θ1 from the close-up position T to the close-up position W as a zoom region, and an angle range θ2 from the close-up position W to the retracted position S outside the zoom region.

In the zoom region, the rectilinear ring 31 and the lens holder 65 are driven by the zoom cam portions 21a and 61a to advance and retreat, whereby the focal length fluctuates within a predetermined range. Outside the zoom range, the rectilinear ring 31 and the lens holder 65 are retracted by the retractable cam portion 21b of the zoom cam ring 11,
It is driven by 61b to advance and retreat, and approaches and separates from the fixed mount 1. In the state shown in FIG. 1, the zoom cam ring 11 is at the far position T, and the rectilinear ring 31 and the lens holder 65 are most advanced together. In the state shown in FIG. At the retracted position S, the rectilinear ring 31 and the lens holder 65 are most retracted.

A changeover switch 71 is provided on the fixed cylinder 3 so as to extend above the zoom ring 5 and the first makeup ring 43.
Is fixed. The changeover switch 71 includes a switch base 73 and a switch knob 75 that slides back and forth within the switch base 73. 4 and 5
As shown in the figures (both are sectional views of the main part of the fixed barrel 3 and the zoom ring 5), a projection 77 is formed on the rear end face of the zoom ring 5, and this projection 77 is formed on the front end face of the fixed barrel 3. The zoom ring 5 rotates within a predetermined angle range by engaging with the formed rotation restricting groove 79. The above-described switch knob 75 causes the retractable restricting pin 81 to protrude and retract in the rotation restricting groove 79. In the forward position, the retractable restricting pin 81 projects as shown in FIG. The movement is stopped within the zoom region (angle range θ1), and at the retracted position, the retracting control pin 81 is retracted as shown in FIG.
2) is acceptable. In the figure, reference numeral 83 denotes a collapsing control pin 8
1 is a coil spring for urging the zoom spring 1 toward the zoom ring 5.

FIG. 6 shows the fixed mount 1 and the fixed cylinder 3.
The flexible printed circuit board 85 shown in the unfolded state is fixed. On the flexible printed circuit board 85, a zoom encoder 89 in which the brush 87 on the zoom cam ring 11 slides, a distance encoder 93 in which the brush 91 on the rectilinear ring 31 slides, and a lens side for processing detection signals of both encoders 89, 93. A CPU 95 and a mount-side contact 97 that contacts the camera-side contact are formed. And
The collapse encoder detection pattern 99 is continuously formed on the zoom encoder 89, and is outside the zoom region (angle range θ2).
Then, the brush 87 on the zoom cam ring 11 side comes into sliding contact with the collapse detection pattern 99.

Next, the operation of the zoom lens barrel according to the present embodiment will be described. When performing zooming on a subject in the shooting state of FIG. 1, the photographer rotates the zoom ring 5 as appropriate. Then, the zoom cam ring 11 integrated with the zoom ring 5 rotates, and is driven by the cam projections 21 and the zoom cam portions 21 a and 61 a of the cam groove 61 to move the straight ring 31 (that is, the focus ring 47) and the lens holder 65. Move forward and backward respectively. Thereby, the distance between the first lens group 45 held by the focus ring 47 and the second lens group 63 held by the lens holder 65 changes continuously,
Zooming is realized. At this time, as shown in FIG. 4, since the collapse restricting pin 81 projects into the rotation restricting groove 79, the zoom cam ring 11 does not deviate outside the zoom region.

In manual focusing, when the photographer turns the focus ring 47 by hand, the male helicoid screw 51 and the female helicoid screw 53 are screwed together. Are screwed back and forth to achieve focusing. In the auto focusing, the focus ring 47 is rotated by being driven by the lens barrel side coupler 55 connected to the camera side coupler.

When the camera is conveyed after photographing is completed, the photographer moves the zoom ring 5 to the left after moving the switch knob 75 of the changeover switch 71 backward. Then, as shown in FIG. 5, since the retractable restricting pin 81 is retracted, the zoom ring 5 rotates from the close-up position W to the retracted position S without any resistance. As a result, the rectilinear ring 31 and the lens holder 65 are driven by the retractable cam portions 21b and 61b of the cam protrusion 21 and the cam groove 61, and retreat to the retracted position S to be in the retracted state shown in FIG. Thereby, the overall length of the lens barrel (that is, the size of the camera) becomes smaller than that at the time of shooting, and transport becomes extremely easy.

On the other hand, when the lens barrel is in the collapsed state, the brush 87 on the zoom cam ring 11 is moved to the collapsed detection pattern 99.
The detection signal is processed by the lens side CPU 95, and a servo drive inhibition signal and a release lock signal are output to the camera side via the mount side contact 97. Thus, when the lens barrel is collapsed, the camera does not operate carelessly, and battery consumption and the like are prevented. At the time of shooting, the zoom position signal and the distance signal detected by the zoom encoder 89 and the distance encoder 93 are processed by the lens-side CPU 95, and then output to the camera through the mount-side contact 97. The camera-side CPU performs various arithmetic processes, and since the procedures and methods are known,
It will not be described in detail here.

The description of the specific embodiment has been completed.
Aspects of the present invention are not limited to this embodiment.
For example, in the above-described embodiment, the zoom ring and the zoom cam ring are provided as separate components. However, these components may be integrally formed to reduce the number of components. In the above embodiment,
Although the present invention is applied to a two-unit retractable zoom lens barrel, it may be applied to a lens having three or more lens groups. Further, the specific configurations of the zoom mechanism and the focus mechanism are not limited to the examples in the above-described embodiment, but can be appropriately changed according to design convenience or the like.

[0023]

According to the present invention, a fixed cylinder fixed to a mount on the camera side is rotatably engaged with the fixed cylinder, and is fixed to the fixed cylinder in the optical axis direction. A zoom ring whose movement is restricted, a zoom cam ring which is rotated in conjunction with the zoom ring and whose movement in the optical axis direction with respect to the fixed barrel is restricted, and a cam formed on the zoom cam ring. And a lens group holding member that moves in the optical axis direction with rotation of the zoom cam ring, wherein the cam drives the cam follower to move the lens group holding member in a zoom region. A zoom cam portion, and a collapsible cam portion that is continuous with the zoom cam portion that drives the cam follower to move the lens group holding member to the mount side outside the zoom region,
Further, since the cam follower is provided with a restricting member for restricting a rotation range of the zoom ring or the zoom cam ring so that the cam follower does not deviate from the zoom cam portion, when a photographer rotates the zoom ring during photographing, the cam follower turns the zoom cam ring. When the photographer rotates the zoom ring in a state where the lens group holding member advances and retreats in the zoom region while the restricting member is retracted by the changeover switch, the cam follower is retracted by the zoom cam ring. The lens group holding member is retracted to the mount side to perform collapsing, thereby facilitating shooting operation and collapsing operation while employing a relatively simple mechanism with a small number of parts. Can be achieved.

In the retractable lens barrel, a zoom encoder that detects a rotational position of the zoom ring in the zoom region and a retractable state detector that detects that the zoom ring is outside the zoom region are provided. When the zoom encoder detects the rotational position of the zoom ring in the zoom area by the zoom encoder, the detection information is output to the camera side, and the control device in the camera performs various calculations and processes. When the retracted state detection device detects that the zoom ring is out of the zoom range, the detection information is output to the camera side, and the control device in the camera performs a process at the time of the retracted state.

In the collapsible lens barrel, a signal output device for outputting a signal to a control device in the camera, and a signal output device when the zoom ring is out of the zoom region. In a camera equipped with a collapsed signal output device that outputs a servo drive inhibition signal and a release lock signal to a control device in the camera, when the retracted state detection device detects that the zoom ring is out of the zoom area, the retracted state is detected. The time signal output device outputs the servo drive prohibition signal and the release lock signal to the control device in the camera, so that an inadvertent operation on the camera side does not occur.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of a retractable zoom lens barrel according to the present invention during photographing.

FIG. 2 is a longitudinal sectional view of the retractable zoom lens barrel according to the present invention when retracted.

FIG. 3 is a development view of a zoom cam ring.

FIG. 4 is a cross-sectional view of main parts of a fixed cylinder and a zoom ring at the time of photographing.

FIG. 5 is a sectional view of a main part of a fixed cylinder and a zoom ring at the time of photographing.

FIG. 6 is a development view of a flexible printed circuit board.

[Explanation of symbols]

 1 Fixed mount 3 Fixed cylinder 5 Zoom ring 11 Zoom cam ring 21 Cam projection 21a Zoom cam section 21b Collapse cam section 31 Straight ring 45 First lens group 45 47 ‥‥ Focus ring 61 ‥‥ Cam groove 61a ‥‥ Zoom cam part 61b ‥‥ Collapsible cam part 63 ‥‥ Second lens group 65 ‥‥ Lens holder 71 ‥‥ Switch 77 ス イ ッ チ Protrusion 79 ‥‥ Rotation restricting groove 81 ‥ ‥ Collapsing control pin 81 85 ‥‥ Flexible printed circuit board 89 ‥‥ Zoom encoder 93 ‥‥ Distance encoder 95 ‥‥ Lens side CPU 97 ‥‥ Mount side contact 99 ‥‥ Collapsing detection pattern 99 L ‥‥ Optical axis

Claims (3)

[Claims] 1. A fixed cylinder fixed to a mount on a camera side, and a zoom that is rotatably engaged with the fixed cylinder and is restricted from moving in the optical axis direction with respect to the fixed cylinder. A ring, a zoom cam ring that rotates in conjunction with the zoom ring and is restricted from moving in the optical axis direction with respect to the fixed barrel, and a cam follower that engages with a cam formed on the zoom cam ring. A lens group holding member that moves in the optical axis direction with the rotation of the zoom cam ring, wherein the cam drives the cam follower to move the lens group holding member in a zoom region; A zoom cam portion for driving the cam follower to move the lens group holding member to the mount side outside the zoom region; and a collapsible cam portion continuous with the zoom follower. So as not to deviate from the zoom cam unit, the zoom ring or retractable zoom lens, characterized in that it comprises a regulating member for regulating the rotation range of the zoom cam ring. 2. A zoom encoder for detecting a rotational position of the zoom ring in the zoom region, and a retractable state detection device for detecting that the zoom ring is out of the zoom region. Claim 1
The collapsible zoom lens barrel described. A signal output device for outputting a signal to a control device in the camera; and a servo drive to the control device in the camera via the signal output device when the zoom ring is out of the zoom region. The retractable zoom lens barrel according to claim 2, further comprising a retractable signal output device that outputs a prohibition signal and a release lock signal.