JP3795484B2 - Lens barrel, barrel unit and camera - Google Patents

Description

  The present invention relates to a lens barrel having a zooming function used as an imaging optical system of a camera such as a video camera and a digital still camera, and an observation imaging optical system of an observation optical device such as a binocular and a telescope. The present invention relates to a lens barrel that responds to an increase in the amount by which an imaging lens is extended in an imaging state accompanying an increase in zoom magnification or a reduction in the thickness of a camera or the like, a barrel unit that uses the lens barrel, and a camera.

In recent years, there has been a further demand for a zoom lens used as a camera taking lens or the like to have a higher magnification and a thinner camera, and the amount of the imaging lens extended in an imaging state has been increasing. Yes. As a configuration of a zoom lens barrel used in a conventional zoom lens of this type, those shown in Patent Document 1, Patent Document 2, and Patent Document 3 are known.
In the configuration shown in Patent Document 1, the fixing member includes a cylindrical lens barrel and a fixing member disposed inside the cylindrical lens barrel, and the lens barrel rotates relative to the fixing member. An electrical contact piece is provided on one of the end surface of the lens and the lens barrel portion that rotates relative to the end surface, and a pattern substrate on which the electrical contact piece is slidably contacted is provided on the other side to perform position detection. Yes. However, in the case of the configuration shown in Patent Document 1, a rotating barrel part or a part for attaching the electrical contact piece and the pattern substrate to the fixing member is required, and the barrel diameter is remarkably increased or the optical axis dimension is measured. Also often affects.

In the configuration of Patent Document 2, light and dark reflectors each composed of a flexible substrate or the like are attached on the zoom ring and the focus ring in the direction around the optical axis, and the light and darkness of each light and dark reflector by rotation of each ring is used as a fixing member. By detecting with the attached detection sensor, the zoom position and the focus position are detected. In this case, the radial dimension of the lens barrel does not increase significantly, but the light / dark reflector on the zoom ring and the light / dark reflector on the focus ring must face the detection sensor attached to the fixed member. For this reason, a configuration in which the light / dark reflector is covered with another member is not allowed, and as a result, the dimension in the optical axis direction becomes extremely long.
Further, as another configuration similar to the configuration of Patent Document 2, a light / dark reflector such as a flexible substrate is attached in the direction around the optical axis on the zoom ring for only the zoom position detection, and this is detected by the position detection sensor. As for the focus position detection, some models detect using a different method. However, even if the increase in the dimension in the optical axis direction is suppressed in this way, the dimension in the radial direction of the lens barrel is limited. It is not easy to simultaneously suppress both dimensions in the optical axis direction and the radial direction, such as increasing.

Furthermore, in the configuration of Patent Document 3, it is shown that a wide range of focal lengths can be realized by inserting / removing a converter lens to / from the zoom optical system to obtain a focal length other than the zooming region of the zoom optical system. However, in this case, a special configuration for inserting / removing the converter lens is required, and large dimensions are required both in the optical axis direction and in the radial direction.
In the conventional configuration including those described in Patent Document 1, Patent Document 2 and Patent Document 3 as described above, the size of the lens barrel in the radial direction and the optical axis direction are detected by a position detection mechanism such as zooming and focusing. It affects at least one of the dimensions and increases the dimension. In any case, the rotating cylinder that moves the lens frame in the optical axis direction has a longer cam groove in the optical axis direction and a drive gear when the amount of extension from the retracted state to the shooting state is large. Then, the dimension in the direction of the optical axis also becomes long.

Japanese Patent Laid-Open No. 11-84215 Japanese Patent No. 2757558 JP-A-6-214147

The present invention has been made in view of the above-described circumstances, and a lens barrel and a lens barrel capable of reducing the size in the optical axis direction of the lens barrel of the zoom lens and suppressing an increase in the size in the radial direction. It aims to provide units and cameras.
The object of the first aspect of the present invention is to reduce the size in the optical axis direction by forming a cam groove having a long feeding amount using the substantially entire length in the optical axis direction of the rotating cylinder in which the cam groove is formed, and further rotating. It is possible to reduce the moment applied to the cylinder and thin the rotating cylinder, effectively suppressing the increase in the radial dimension of the lens barrel, and devising the setting of the position sensor operating range to turn on the power Then, the zoom lens can be reset once before it becomes ready for photographing, and a lens barrel that can obtain more accurate zoom position information is provided.
The object of Claim 2 of the present invention is to obtain a good image by eliminating unwanted light rays such as light leakage, flare and ghost due to openings such as cam groove holes and notches in the rotating cylinder. It is in providing a lens barrel.
The object of claim 3 of the present invention is to simplify the structure without restricting the relative positional relationship other than the rotation direction around the optical axis, particularly in the relative positioning engagement of the outer cylinder with the rotating cylinder. Another object of the present invention is to provide a lens barrel that can reduce the assembly time during manufacture.
A fourth object of the present invention is to provide a lens barrel that makes it possible to increase the zoom adjustment range by making the movable range of the drive gear wider than the actual use range.

It is an object of the present invention to provide a lens barrel that can simplify the structure of the rotary cylinder and stabilize the shape of the cam groove to obtain a good image.
An object of claim 6 of the present invention is to provide a lens barrel that can effectively suppress the radial dimension of the lens barrel, particularly by the shape of the rib for detecting the zoom position. .
The object of the seventh aspect of the present invention is to devise the arrangement of a position sensor such as a photo interrupter in particular, to suppress the time change of the position sensor, and to obtain appropriate position detection information stably over a long period of time. , moreover Ru near to provide a lens barrel capable of shape simplification of signal transmission paths, such as a flexible substrate.

An object of claim 8 of the present invention is to provide a lens barrel that can reduce and eliminate errors between actual machines caused by variations in manufacturing.
An object of claim 9 of the present invention is to provide a lens barrel that can obtain accurate focal length information with respect to a zoom reference position and set a focus operating range appropriately.
The object of the tenth aspect of the present invention is to provide a lens barrel unit that can ensure a small size and good performance without increasing the size of the zoom lens barrel.
An object of claim 11 of the present invention is to provide a camera which can ensure a small size and good performance without increasing the size of the zoom lens barrel.

In order to achieve the above-described object, the lens barrel according to the present invention described in claim 1
At least one lens frame holding a lens element;
A fixed cylinder that linearly guides the lens frame along the optical axis direction;
A base for fixing and holding the fixed cylinder;
It is arranged outside the fixed cylinder, is engaged with the lens frame via a cam mechanism, and rotates around the optical axis to move the lens frame by a predetermined amount along the optical axis direction, A rotating cylinder that causes zooming in the lens element;
An outer cylinder that is disposed outside the rotating cylinder and rotates around the optical axis integrally with the rotating cylinder;
In a lens barrel with
The outer cylinder is
A drive gear for driving the lens frame;
A finder coupling portion coupled to the finder for interlocking with the finder,
Zoom position detecting means for detecting the zoom position of the lens element held by the lens frame ,
The zoom position detecting means moves a position detection sensor provided in the vicinity of the outer cylinder from an angular position corresponding to a short focal end of zooming of the lens element from an angular position corresponding to a storage position of the lens frame in the outer cylinder. Is also configured to be turned off or on in a predetermined driving region smaller than the backlash angle of the lens barrel and turned on or off in other driving regions .

The lens barrel according to the present invention described in claim 2 is the lens barrel of claim 1,
The rotating cylinder has an opening including a cam groove hole constituting the cam mechanism, and the outer cylinder is formed in a cylindrical shape covering at least the opening including the cam groove hole of the rotating cylinder. It is a feature.
The lens barrel according to the present invention described in claim 3 is the lens barrel according to claim 1 or 2,
The outer cylinder is configured to engage with the rotating cylinder so as to operate integrally while maintaining a predetermined positional relationship between them only in the rotation direction around the optical axis.

The lens barrel according to the present invention described in claim 4 is the lens barrel according to any one of claims 1 to 3,
The drive gear is formed over a range at least as much as the rotatable angle of the rotary cylinder.
The lens barrel according to the present invention described in claim 5 is the lens barrel according to any one of claims 1 to 4,
The finder connecting portion zooms the finder corresponding to the rotating operation of the rotating cylinder at least in the effective imaging zooming region of the lens element.

A lens barrel according to the present invention described in claim 6 is the lens barrel according to any one of claims 1 to 5,
The zoom position detecting means moves the position sensor provided in the vicinity of the outer cylinder from an angular position corresponding to the short focal end of zooming of the lens element from an angular position corresponding to the storage position of the lens frame in the outer cylinder. In order to turn off or on in a predetermined drive region up to an angle position just before the backlash angle of the lens barrel and on or off in other regions, the predetermined drive region of the outer tube It is characterized by including a rib that is disposed over a corresponding rotation angle range and extends in a direction parallel to the optical axis.
A lens barrel according to a seventh aspect of the present invention is the lens barrel according to the sixth aspect,
It said position sensor is fixed to the base that has features that it is disposed at a predetermined position.

The lens barrel according to the present invention described in claim 8 is the lens barrel according to any one of claims 6 to 7 ,
The position sensor is configured to write in a storage device at least one of a storage position, a short focal end position, and a long focal end position with the on / off position of the position sensor as a zoom reference of the lens barrel. Yes.
The lens barrel according to the present invention described in claim 9 is the lens barrel according to claim 8 ,
The position information is at least one of the number of pulses of a pulse motor as a drive source and an encoder output count value of a DC motor as a drive source.
According to a tenth aspect of the present invention, a lens barrel unit according to the present invention includes the lens barrel according to any one of the first to ninth aspects, and a finder coupled to the lens barrel via a finder coupling portion. It is characterized by having.
According to an eleventh aspect of the present invention, a camera according to the present invention includes the lens barrel unit according to the tenth aspect.

[Action]
That is, a lens barrel according to a first aspect of the present invention fixes and holds at least one lens frame that holds a lens element, a fixed barrel that linearly guides the lens frame along an optical axis direction, and the fixed barrel. A base and an outer side of the fixed cylinder are engaged with the lens frame via a cam mechanism. The lens frame is moved by a predetermined amount along the optical axis direction by rotating around the optical axis. A lens barrel including: a rotating cylinder that causes zooming of the lens element; and an outer cylinder that is disposed outside the rotating cylinder and rotates around the optical axis integrally with the rotating cylinder.
The outer cylinder detects a zoom position of the lens element held by the lens frame, a driving gear for driving the lens frame, a finder coupling unit coupled to the finder to interlock with the finder. Zoom position detecting means for,
The zoom position detecting means moves a position detection sensor provided in the vicinity of the outer cylinder from an angular position corresponding to a short focal end of zooming of the lens element from an angular position corresponding to a storage position of the lens frame in the outer cylinder. Also, it is configured such that it is turned off or on in a predetermined drive region up to an angle position just before the backlash angle of the lens barrel and turned on or off in other drive regions .
With such a configuration, the outer cylinder provided on the outer side of the rotating cylinder in which the cam groove is formed is provided with the drive gear, the finder connecting portion, and the zoom position detecting means, thereby using the almost entire length of the rotating cylinder in the optical axis direction. A cam groove with a long feeding amount can be formed, the dimension in the optical axis direction is reduced, and further, the moment of the driving gear and the moment of the finder connecting portion are not directly applied to the rotating cylinder. The increase in the radial dimension of the lens barrel can be suppressed to the minimum necessary level . With such a configuration, in particular, the on / off switching angle position of the position sensor such as a photo interrupter can be shortened. Set by deviating from the angle position corresponding to the focus end position to the storage side by an angle equal to or less than the backlash, and zooming when moving to the short focus end position even when zooming in the shooting state Set can apply, it is possible to obtain a more accurate zoom position information.

A lens barrel according to a second aspect of the present invention is the lens barrel according to the first aspect, wherein the rotating cylinder has an opening including a cam groove hole constituting the cam mechanism, and the outer cylinder. However, it is formed in a cylindrical shape covering at least an opening including the cam groove hole of the rotating cylinder.
With such a configuration, in particular, openings formed in the rotating cylinder such as cam slots and notches are blocked by the outer cylinder to eliminate undesirable light rays such as light leakage, flare and ghost. A good image can be obtained.
A lens barrel according to a third aspect of the present invention is the lens barrel according to the first or second aspect, wherein the outer cylinder is predetermined between each other only in the rotational direction around the optical axis with respect to the rotary cylinder. Are engaged so as to operate integrally.
With such a configuration, in particular, the outer cylinder is engaged with the rotating cylinder so as to rotate integrally with a predetermined relative positional relationship only in the rotation direction around the optical axis. It is possible to simplify the structure without restricting the general positional relationship, and to reduce the assembly time during manufacturing.
A lens barrel according to a fourth aspect of the present invention is the lens barrel according to any one of the first to third aspects, wherein the drive gear is at least in a range equal to or greater than an angle of rotation of the rotary barrel. Is formed over.
With such a configuration, it is possible to increase the zoom adjustment range, particularly when the effective range of the drive gear is set to be greater than the actual use range.

A lens barrel according to a fifth aspect of the present invention is the lens barrel according to any one of the first to fourth aspects, wherein the finder connecting portion is at least an effective imaging zooming region of the lens element. The viewfinder is zoomed in response to the rotation of the rotating cylinder.
With such a configuration, in particular, a finder connecting portion is provided in the outer cylinder, the structure of the rotating cylinder is further simplified, and the shape of the cam groove can be further stabilized and a good image can be obtained.
A lens barrel according to a sixth aspect of the present invention is the lens barrel according to any one of the first to fifth aspects, wherein the zoom position detecting means includes a position sensor provided in the vicinity of the outer cylinder, From the angular position corresponding to the storage position of the lens frame in the outer cylinder to the angular position before the angular position corresponding to the short focal end of zooming of the lens element by an angle smaller than the backlash angle of the lens barrel . In a predetermined drive area, the outer cylinder is arranged over a rotation angle range corresponding to the predetermined drive area and turned in a direction parallel to the optical axis so as to be turned off or on and in other areas to be turned on or off. Includes extending ribs.
With this configuration, in particular, with the ribs of the zoom position detecting means is formed in a direction parallel to the optical axis, it becomes possible to effectively suppress the radial dimension of the lens barrel, in particular, the photointerrupter The position angle on / off switching position of the position sensor, etc., is set so as to deviate from the angle position corresponding to the short focus end position by an angle equal to or less than the backlash, and the short focus even when zooming in the shooting state. The zoom can be reset when moved to the end position, and more accurate zoom position information can be obtained.

A lens barrel according to a seventh aspect of the present invention is the lens barrel according to the sixth aspect, wherein the position sensor is fixed to the base and disposed at a predetermined position.
With such a configuration, in particular, the position sensor such as a photo interrupter is adjusted and fixed to the base, a change with time of the position sensor is suppressed, and appropriate position detection information can be obtained stably over a long period of time. It can, moreover that Do is possible to shape simplifies the signal transmission path such as a flexible substrate.

A lens barrel according to an eighth aspect of the present invention is the lens barrel according to any one of the sixth to seventh aspects, wherein an on / off position of the position sensor is defined as a zoom reference of the lens barrel. The position information of at least one of the storage position, the short focus end position, and the long focus end position is written in the storage device.
With such a configuration, in particular, in a storage device such as an EEPROM (electrically erasable programmable read-only memory), the storage position and the short focal end of the lens barrel with the on / off position of the position sensor as a zoom reference By writing the position information of at least one of the position and the long focal end position, it is possible to reduce and eliminate errors between actual machines due to variations in manufacturing.

A lens barrel according to a ninth aspect of the present invention is the lens barrel according to the eighth aspect , wherein the position information includes a pulse number of a pulse motor as a drive source and an encoder output count value of a DC motor as a drive source. At least one.
With such a configuration, in particular, from the zoom reference position, at least one of the pulse number of the pulse motor and the encoder output count value of the DC motor is stored as information in the storage device, and accurate focal length information with respect to the zoom reference position is obtained. As a result, the focus operation range can be set appropriately.
A lens barrel unit according to a tenth aspect of the present invention includes the lens barrel according to any one of the first to ninth aspects, and a finder coupled to the lens barrel via a finder coupling portion.
With such a configuration, in particular, the size of the zoom lens barrel can be increased by providing the drive gear, the finder connecting portion, and the zoom position detecting means on the outer cylinder outside the rotating cylinder in which the cam groove is formed. Therefore, it is possible to ensure a small size and good performance.
A camera according to an eleventh aspect of the present invention includes the lens barrel unit according to the tenth aspect .
With such a configuration, the dimensions of the zoom lens barrel can be obtained by using a barrel unit including a drive gear, a finder connecting portion, and a zoom position detecting unit on the outer cylinder outside the rotating cylinder in which the cam groove is formed. It is possible to ensure a small size and good performance without increasing.

According to the present invention, it is possible to provide a lens barrel, a barrel unit, and a camera that can reduce the size in the optical axis direction of the barrel of the zoom lens and suppress the increase in the radial size. .
That is, according to the lens barrel of claim 1 of the present invention,
At least one lens frame holding a lens element;
A fixed cylinder that linearly guides the lens frame along the optical axis direction;
A base for fixing and holding the fixed cylinder;
It is arranged outside the fixed cylinder, is engaged with the lens frame via a cam mechanism, and rotates around the optical axis to move the lens frame by a predetermined amount along the optical axis direction, A rotating cylinder that causes zooming in the lens element;
An outer cylinder that is disposed outside the rotating cylinder and rotates around the optical axis integrally with the rotating cylinder;
In a lens barrel with
The outer cylinder is
A drive gear for driving the lens frame;
A finder coupling portion coupled to the finder for interlocking with the finder,
Zoom position detecting means for detecting the zoom position of the lens element held by the lens frame;
Equipped with,
The zoom position detecting means moves a position detection sensor provided in the vicinity of the outer cylinder from an angular position corresponding to a short focal end of zooming of the lens element from an angular position corresponding to a storage position of the lens frame in the outer cylinder. Also , the cam groove is configured to be turned off or on in a predetermined driving area up to an angle position just before the backlash angle of the lens barrel and turned on or off in other driving areas. Forming a cam groove with a long feed amount that uses almost the entire length of the rotating cylinder in the optical axis direction to reduce the dimension in the optical axis direction, and to reduce the moment applied to the rotating cylinder and to make the rotating cylinder thinner it is possible to effectively suppress an increase in the radial dimension of the cylinder, by devising the setting of the operating range of the position sensor, the photographable state after turning on the power The zoom can be reset once before shooting, and more accurate zoom position information can be obtained. In particular, when the predetermined angle is smaller than the backlash angle of the lens barrel, Even when zooming is performed, zoom reset can be performed when the zoom lens is moved to the short focal end position, and more accurate zoom position information can be obtained.

According to the lens barrel of claim 2 of the present invention, in the lens barrel of claim 1, the rotating cylinder has an opening including a cam groove hole constituting the cam mechanism, and the outer cylinder. Is formed in a cylindrical shape covering at least the opening including the cam groove hole of the rotating cylinder, in particular, light leakage, flare, ghost, etc. due to the opening of the rotating cylinder such as the cam groove hole and the notch. A favorable image can be obtained by eliminating undesirable light rays.
According to the lens barrel of the third aspect of the present invention, in the lens barrel of the first or second aspect, the outer cylinder is predetermined between each other only in the rotation direction around the optical axis with respect to the rotary cylinder. In particular, in the relative positioning engagement of the outer cylinder with respect to the rotating cylinder, the relative position other than the rotation direction around the optical axis is maintained. Without restricting the relationship, the structure can be made simpler and the assembly time during manufacturing can be reduced.
According to the lens barrel of claim 4 of the present invention, in the lens barrel of any one of claims 1 to 3, the drive gear is at least in a range equal to or greater than the angle by which the rotary cylinder can be rotated. In particular, the zoom adjustment range can be increased by making the movable range of the drive gear wider than the actual use range.

According to the lens barrel of claim 5 of the present invention, in the lens barrel of any one of claims 1 to 4, the finder connecting portion is at least about an effective imaging zooming region of the lens element. By zooming the finder in response to the rotation operation of the rotating cylinder, in particular, the structure of the rotating cylinder can be further simplified, the cam groove shape can be further stabilized, and a good image can be obtained.
According to the lens barrel of claim 6 of the present invention, in the lens barrel of any one of claims 1 to 5, the zoom position detecting means includes a position sensor provided in the vicinity of the outer cylinder , From the angular position corresponding to the storage position of the lens frame in the outer cylinder to the angular position before the angular position corresponding to the short focal end of zooming of the lens element by an angle smaller than the backlash angle of the lens barrel. In order to turn off or on in a predetermined drive region and on or off in other regions, the outer cylinder is disposed over a rotation angle range corresponding to the predetermined drive region and in a direction parallel to the optical axis. by including a rib extending, by the shape of ribs for zoom position detection, it is possible to effectively suppress the radial dimension of the lens barrel, in particular the operation of the position sensor By devising the setting of the range, it is possible to reset the zoom once before turning on the power and before shooting is possible, and to obtain more accurate zoom position information. By setting again to an angle smaller than the backlash angle of the lens barrel, zoom reset can be applied when moving to the short focus end position even when zooming in the shooting state, and a more accurate zoom position Information can be obtained.
According to the lens barrel of claim 7 of the present invention, in the lens barrel of claim 6, the position sensor is fixed to the base and disposed at a predetermined position, and in particular, the position of a photo interrupter or the like. By devising the arrangement of the sensor, it is possible to suppress time-dependent changes of the position sensor, to obtain stable position detection information stably over a long period of time, and to simplify the shape of the signal transmission path such as a flexible substrate it can.

According to the lens barrel of claim 8 of the present invention, in the lens barrel of any one of claims 6 to 7 , the on / off position of the position sensor is defined as the zoom reference of the lens barrel. With the configuration in which at least one of the storage position, the short focus end position, and the long focus end position is written in the storage device, errors between actual machines due to variations in manufacturing can be reduced and removed.

According to the lens barrel of claim 9 of the present invention, in the lens barrel of claim 8 , the position information includes the number of pulses of the pulse motor as the drive source and the encoder output count value of the DC motor as the drive source. By being at least one of them, in particular, it is possible to obtain accurate focal length information with respect to the zoom reference position and appropriately set the focus operation range.
Furthermore, according to the lens barrel unit of claim 10 of the present invention, the lens barrel according to any one of claims 1 to 9 and a finder coupled to the lens barrel via a finder coupling portion. In particular, it is possible to ensure a small size and good performance without increasing the size of the zoom lens barrel.
According to the camera of the eleventh aspect of the present invention, by providing the lens barrel unit of the tenth aspect , it is possible to ensure a small size and good performance without particularly increasing the size of the zoom lens barrel. .

Hereinafter, based on an embodiment of the present invention, a lens barrel, a barrel unit, and a camera of the present invention will be described in detail with reference to the drawings.
1 to 4 show a configuration of a lens barrel unit according to the present invention configured using a lens barrel according to an embodiment of the present invention. FIG. 1 is a perspective view showing the external appearance of the lens barrel unit viewed obliquely from below, FIG. 2 is a longitudinal sectional view along the optical axis of the lens barrel in the lens barrel unit of FIG. 1, and FIG. FIG. 4 is an exploded perspective view of the lens barrel portion of the barrel unit, and FIG. 4 is a developed view of the rotary barrel schematically showing the cam groove hole shape and the bottomed groove of the rotary barrel. The lens barrel unit including the lens barrel shown in FIGS. 1 to 4 is housed in, for example, a camera body (not shown) to constitute the camera according to the present invention.
The lens barrel unit shown in FIGS. 1 to 4 includes lens frames 11, 12 and 13, a fixed cylinder 14, a rotating cylinder 15, a focus motor 16, an outer cylinder 17, a finder cam 18, a finder 19 and a base 20. . The lens frame 11 is provided with a cam follower 11a, and the lens frame 12 is provided with a cam follower 12a. The fixed cylinder 14 has a key groove hole 14a, the rotary cylinder 15 has a cam groove hole 15a and a bottom. A groove 15b is provided, and the outer cylinder 17 is provided with a drive gear 17a, a finder connecting portion 17b, a rib 17c, and a convex portion 17d.

That is, the lens barrel includes lens frames 11, 12, and 13. The lens frames 11 and 12 are slidably held on the inner peripheral surface of the fixed cylinder 14 and are parallel to the fixed cylinder 14 in the optical axis direction. The slit-shaped key groove hole 14a formed on the lens frame 11 and the cam followers 11a and 12a of the lens frames 11 and 12 are guided in a straight line along the optical axis direction. The cam followers 11a and 12a of the lens frames 11 and 12 are further fitted into slit-shaped cam grooves 15a formed by presenting a predetermined cam surface on the rotary cylinder 15, and the lens frame 11 and 12 moves forward and backward in the optical axis direction.
Further, the lens frame 13 is fitted with a straight guide shaft (not clearly shown) parallel to the optical axis direction, and a lead screw formed on the output shaft of the focus motor 16 is screwed. Accordingly, the lens frame 13 is guided in a straight line along the optical axis direction, and is driven by a lead screw of the focus motor 16 to move forward and backward along the optical axis direction. An outer cylinder 17 is disposed outside the rotating cylinder 15 and rotates integrally with the rotating cylinder 15 around the optical axis. In this case, a bottomed groove 15b extending in parallel with the optical axis direction is formed on the outer surface of the rear end portion of the rotating cylinder 15, that is, on the imaging surface side (corresponding to the right rear side in FIG. 3 and the upper side in FIG. 4). A convex portion 17d is formed on the inner surface of the corresponding portion of the outer cylinder 17, and the convex portion 17d is engaged with the bottomed groove 15b so as to cover the outer cylinder 17 from the rear side of the rotating cylinder 15. The outer cylinder 17 and the rotating cylinder 15 are integrally rotated about the optical axis.

The outer cylinder 17 is provided with a driving gear 17a for transmitting the rotational driving force to the outer cylinder 17, and the driving force is transmitted to the driving gear 17a by a driving motor and a reduction gear (not shown). Is done. The outer cylinder 17 is also provided with a finder connecting portion 17b to the finder 19, and a finder cam 18 is connected to the connecting portion 17b, and the finder connecting portion 17b and the finder cam 18 are used to Zooming of the finder 19 is performed in conjunction with the cylinder 17. Further, the outer cylinder 17 is also formed with a rib 17c as a zoom position detecting means, and the photo interrupter 21 as a position sensor which is appropriately adjusted and fixed to the base 20 is turned off in a predetermined drive region. In other cases, the rib 17c is set to be on.
In this embodiment, at least one of the encoder output count value of the DC motor (not shown) and the number of pulses of the pulse motor as the drive source is used as position information.

As shown in the development view of FIG. 4, the drive gear (17 a) and the finder connecting portion (17 b) are provided in the outer cylinder 17, and these do not exist in the rotating cylinder 15, so that the rotating cylinder 15 is almost in the optical axis direction. The cam slot 15a can be formed using the entire length, and the dimension of the lens barrel in the optical axis direction can be suppressed to the minimum value.
As described above, the outer cylinder 17 is provided outside the rotating cylinder 15 in which the cam groove hole 15a is formed, and the outer gear 17 is provided with the drive gear 17a, the finder connecting portion 17b, the rib 17c as the zoom position detecting means, and the like. Thus, the cam slot 15a having a long feeding amount can be formed by using the entire length of the rotating cylinder 15 in the optical axis direction, the dimension in the optical axis direction can be reduced, and the moment of the drive gear 17a and the finder can be applied to the rotating cylinder 15. since the moment of consolidated portion 17b is not applied, the rotary cylinder 15 is formed to be thin, Ru can suppress an increase in the radial dimension of the lens barrel to a minimum.
The on / off switching operation of the position sensor such as the photo interrupter 21 can be set to a rotation position that is returned from the storage position by a predetermined preliminary angle in the storage position direction from the short focus end position, and can be photographed from the power-on. before a state, once it is possible to zoom reset, that Do is possible to obtain an accurate zoom position information.
By setting the on / off switching operation of the position sensor such as the photo interrupter 21 to the storage position side by an amount equal to or less than the back focus end position relative to the short focus end position, the camera moves to the short focus end position even when zooming in the shooting state. It makes it possible to apply a zoom reset when is, it becomes possible to obtain a more accurate zoom position information (or, corresponding to claim 1).
Further, the outer cylinder 17 is used to shield the cam groove hole 15a of the rotating cylinder 15 and the opening such as the cutout portion, thereby eliminating unwanted light rays such as light leakage, flare, and ghost, and a good photograph. Or the like (corresponding to claim 2).

The outer cylinder 17 and the rotating cylinder 15 are integrally rotated while maintaining a predetermined relative positional relationship only in the rotation direction around the optical axis, thereby simplifying the structure and reducing assembly time during manufacturing. (Corresponding to claim 3).
By making the range where the drive gear 17a is disposed wider than the actual use range beyond the actual use range, the zoom adjustable range can be increased (corresponding to claim 4).
By providing the outer cylinder 17 with a finder connecting portion 17b, the rotating cylinder 15 can have a simpler structure, and the shape of the cam slot 15a can be stabilized to obtain a good image such as a photograph. 5).
The zoom position detecting means such as ribs 17c are formed in a direction parallel to the optical axis, Ru can be suppressed effectively increase the radial dimension of the lens barrel.
The switching operation of the on / off position sensor such as a photo-interrupter 21, the storage position, by setting the rotational position returned by a predetermined angular degree to the stored position direction than the short focal end position, can be photographed from the power-on before a state, once it is possible to zoom reset, that Do is possible to obtain an accurate zoom position information.
By setting the on / off switching operation of the position sensor such as the photo interrupter 21 to the storage position side by an amount equal to or less than the back focus end position relative to the short focus end position, the camera moves to the short focus end position even when zooming in the shooting state. When this is done, it is possible to perform zoom reset, and it is possible to obtain more accurate zoom position information (corresponding to claim 6 ).
A position sensor, for example, a photo interrupter 21 is fixed to the base 20 as a predetermined relative positional relationship so that a change over time of the photo interrupter 21 can be suppressed, and a signal can be stably obtained over a long period of time. The shape of the path, for example a flexible substrate, can also be made simpler (corresponding to claim 7).

By writing each position information in a storage device such as an EEPROM, it is possible to correct variations among devices and eliminate errors (corresponding to claim 8 ).
By storing the number of pulses of the pulse motor or the count value of the encoder of the DC motor from the zoom reference position in the storage device as position information, it is possible to obtain accurate focus information, and set the focus operating range appropriately (Corresponding to claim 9 ).
By providing the outer cylinder 17 provided with the driving gear 17a of the lens barrel, the finder connecting portion 17b, and the rib 17c as the zoom position detecting means on the outer side of the rotating cylinder 15, it is possible to increase the size of the lens barrel without increasing Performance can be ensured (corresponding to claims 10 and 11 ).

It is the perspective view seen from the slanting lower part which shows the external appearance of the structure of the lens-barrel unit based on this invention comprised using the lens-barrel concerning one embodiment of this invention. It is a longitudinal cross-sectional view along the optical axis of the lens barrel in the lens barrel unit of FIG. It is a disassembled perspective view of the lens-barrel part in the lens-barrel unit of FIG. FIG. 3 is a development view of a rotating cylinder schematically showing an outline of a cam groove hole shape and a bottomed groove of the rotating cylinder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 12, 13 Lens frame 14 Fixed cylinder 15 Rotating cylinder 16 Focus motor 17 Outer cylinder 18 Viewfinder cam 19 Viewfinder 20 Base 11a, 12a Cam follower 14a Key groove hole 15a Cam groove hole 15b Bottom groove 17a Drive gear 17b Viewfinder coupling part 17c rib 17d convex part

Claims (11)

At least one lens frame holding a lens element;
A fixed cylinder that linearly guides the lens frame along the optical axis direction;
A base for fixing and holding the fixed cylinder;
It is arranged outside the fixed cylinder, is engaged with the lens frame via a cam mechanism, and rotates around the optical axis to move the lens frame by a predetermined amount along the optical axis direction, A rotating cylinder that causes zooming in the lens element;
An outer cylinder that is disposed outside the rotating cylinder and rotates around the optical axis integrally with the rotating cylinder;
In a lens barrel with
The outer cylinder is
A drive gear for driving the lens frame;
A finder coupling portion coupled to the finder for interlocking with the finder,
Zoom position detecting means for detecting the zoom position of the lens element held by the lens frame;
Equipped with,
The zoom position detecting means moves a position detection sensor provided in the vicinity of the outer cylinder from an angular position corresponding to a short focal end of zooming of the lens element from an angular position corresponding to a storage position of the lens frame in the outer cylinder. Is also configured to be turned off or on in a predetermined drive region up to an angle position before this by an angle smaller than the backlash angle of the lens barrel and turned on or off in other drive regions. Lens barrel. The rotating cylinder has an opening including a cam groove hole constituting the cam mechanism, and the outer cylinder is formed in a cylindrical shape covering at least the opening including the cam groove hole of the rotating cylinder. The lens barrel according to claim 1, wherein   The outer cylinder is configured to engage with the rotating cylinder so as to operate integrally while maintaining a predetermined positional relationship between them only in the rotation direction around the optical axis. The lens barrel according to claim 1 or 2.   The lens barrel according to any one of claims 1 to 3, wherein the drive gear is formed over a range at least equal to an angle of rotation of the rotary cylinder.   5. The finder connecting unit according to claim 1, wherein at least an effective imaging zooming area of the lens element zooms the finder corresponding to a rotation operation of the rotating cylinder. 6. The lens barrel described in 1. The zoom position detecting means moves a position sensor provided in the vicinity of the outer cylinder from an angular position corresponding to a short focal end of zooming of the lens element from an angular position corresponding to the storage position of the lens frame in the outer cylinder. In order to turn off or on in a predetermined drive region up to an angle position just before the backlash angle of the lens barrel and on or off in other regions, the predetermined drive region of the outer tube The lens barrel according to any one of claims 1 to 5, further comprising a rib disposed in a corresponding rotation angle range and extending in a direction parallel to the optical axis.   The lens barrel according to claim 6, wherein the position sensor is fixed to the base and disposed at a predetermined position. The position sensor is configured to write position information of at least one of a storage position, a short focus end position, and a long focus end position with the on / off position of the position sensor as a zoom reference of the lens barrel in a storage device. The lens barrel according to any one of claims 6 to 7 . 9. The lens barrel according to claim 8 , wherein the position information is at least one of a pulse number of a pulse motor as a drive source and an encoder output count value of a DC (direct current) motor as a drive source. A lens barrel unit comprising: the lens barrel according to any one of claims 1 to 9 ; and a finder coupled to the lens barrel via a finder coupling portion. A camera comprising the lens barrel unit according to claim 10 .

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