JPH1010403A - Optical device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] An optical system member can be pressed against a cam portion in a direction parallel to an optical axis only in a region where backlash between the optical system member and a cam portion needs to be removed, and a pressing force in other regions. Provided is an optical device that can reduce the driving load of the zoom ring by reducing the zooming. SOLUTION: Optical system members 1 and 3 are cam members 6 by guide portions 6a and 6b of cam members 6 and urging members 17 and 19.
A restricting means capable of changing to a state of being pressed or non-pressed on the guide portions 6a, 6b in accordance with the magnification switching range and the focus adjustment range of the guide portions 6a, 6b, or of which the pressing force on the guide portions is variable. To be configured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device for switching a magnification of a taking lens system and adjusting a focus by rotating a zoom ring.

[0002]

Prior to the present invention, the applicant of the present invention has an optical system in which a zoom position is selected (magnification switching) and a focus is adjusted by rotating a zoom ring in a two-unit zoom lens comprising two lens groups. Proposed device (Tokho 6-)
No. 100707).

FIG. 14 is a schematic view of a main part of a magnification switching operation and a focus adjusting operation in the optical device, and FIG. 15 is an explanatory diagram showing a movement locus of each lens group of the optical device.

In FIG. 14, reference numeral 101 denotes a convex lens unit, 102 denotes a shutter blade also serving as an aperture, 103 denotes a concave lens unit, and 104 denotes a photographing surface. The figure drawn on the upper side shows a state in which the lens focus is set to で in the state of a short focal length (hereinafter, referred to as WIDE), and the figure drawn on the lower side shows a state of a long focal length (hereinafter, referred to as TELE). Indicates the state in which the lens focus is closest, and arrows C, M1 to M4, and N1 to N3 shown in the middle thereof indicate the lens units 101, for each rotation angle of the zoom ring drawn on the right side. 103 represents the position on the optical axis. That is, the arrows C, M1 to M4, and N1 to N3 represent the movement progress (trajectory) of each lens group when the horizontal axis is the movement amount of the lens and the vertical axis is the rotation angle of the zoom ring.

Here, the magnification switching operation and the focus adjustment operation of the optical device will be described. When the zoom ring is rotated by 30 ° from the state where the lens focus is set to ∞ at the WIDE zoom position shown in FIG. Convex lens unit 10
1. Shutter blade 102 and concave lens unit 103
Move as shown in the figure.

For this reason, there is no change in the magnification of the photographing lens system including the convex lens unit 101 and the concave lens unit 103 during the arrow M1, and the rotation of the zoom ring causes the WID to change.
The focus adjustment is performed in the E state, and the lens is brought into the closest focusing distance at the position of 30 ° (see FIG. 15).

When the photographer wants to increase the magnification a little more and switches to a normal (hereinafter referred to as NOM) mode, the zoom ring stops at a position between 120 ° and 150 ° based on the distance measurement information. . That is, as already evident, when the rotation of the zoom ring comes to 120 °,
In the NOM state (a state of intermediate magnification between TELE and WIDE), the lens position is focused on ∞. When the zoom ring is further rotated from this state, the entire photographing lens system is extended for 30 ° as in the case of WIDE, and focus adjustment is performed in the NOM state.

Similarly, in the case of TELE, if the zoom ring is rotated by 180 °, the lens comes to the position where the lens focus is adjusted to ∞ by TELE, and if the zoom ring is further rotated,
The lens position is such that the lens is in focus at a short distance in the TELE state.

With the above configuration, the optical device performs magnification adjustment (magnification switching area) and focus adjustment (focus adjustment) only by rotating a single zoom ring.

[0010] Further, the applicant of the present invention disposes the first lens unit, the second lens unit, and the first lens unit and the second lens unit in a direction parallel to the optical axis in the same optical path. A guide member having a guide portion for changing the relative position of the first lens unit and the second lens unit, and pressing these lens units against the guide portion of the guide member to form an optical axis; There has been proposed a lens device provided with a biasing means acting to remove backlash in the parallel direction.
No. 0).

[0011]

By the way, the optical device disclosed in the above-mentioned Japanese Patent Publication No. 6-100707 can switch the magnification and adjust the focus only by rotating a single zoom ring. Despite the benefits,
As is clear from FIGS. 14 and 15 described above, the magnification switching area (the arrow N shown in FIGS. 14 and 15) when the magnification is switched.
The amount of lens movement in the range of 1, N2, and N3 is determined by the focus adjustment range (the arrow M shown in FIGS. 14 and 15) when performing focus adjustment.
(Range of M1, M3, M4, M4), the driving load of the zoom ring at the time of magnification switching is generally larger than the driving load of the zoom lens at the time of focus adjustment. For this reason, in each of the above-described magnification switching ranges N1, N2, and N3, it is necessary to increase the rotational driving force of the zoom ring. The focus adjustment areas M1, M1, M3, and M4 are areas for adjusting the focus of the photographing lens system. In order to ensure optical performance, the focus adjustment areas M1, M1, M3, and M4 are used when the photographing lens system moves through the focus adjustment area. The rush needs to be removed.

Therefore, in order to ensure optical performance,
As in the invention of the above-mentioned JP-A-4-101110,
If the first lens unit and the second lens unit are separated by an urging member in a direction parallel to the optical axis and pressed against a cam portion (not shown) of the zoom ring, backlash of the cam portion is removed. The pressing force increases the frictional force of the cam portion, and the driving load of the zoom ring is further increased throughout the magnification switching area and the focus adjustment area, so that it cannot be an effective solution.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the optical device, and is directed to an optical device in which a photographic lens system alternately moves between a focus adjustment area and a magnification switching area. The optical member can be pressed against the cam in the direction parallel to the optical axis only in the area where the backlash between the optical member and the cam needs to be removed. In other areas, the pressing force is reduced and the driving load of the zoom ring is reduced. It is a first object of the present invention to provide an optical device capable of reducing the amount of light.

It is a second object of the present invention to provide an optical device which can speed up the driving of the zoom ring and can quickly perform the focus switching operation of the optical system members.

It is a third object of the present invention to provide an optical device which can reduce the driving load of the zoom ring in a region where the magnification switching in which the driving load of the zoom ring is particularly large is performed.

[0016]

According to the present invention, there is provided an optical apparatus for achieving the above-mentioned first object, comprising: [1] an optical system member movable in an optical axis direction, and the optical system member having a predetermined locus. A rotatable cam member having a guide portion having first and second regions alternately guiding the optical system member in the optical axis direction so as to draw, and a rotatable cam member for guiding the optical system member to the cam member A biasing member for pressing the cam member in a direction parallel to the optical axis direction, and the guide portion of the cam member and the biasing member move the optical system member in accordance with a position of the cam member in the guide portion of the cam member. (2): in the direction of the optical axis, a regulating means capable of changing to a state of being pressed or non-pressed on the guide portion of the member, or having a variable pressing force on the guide portion. A plurality of movable optical system members and these plurality of optical system members A rotatable cam member having a guide portion having first and second regions that alternately guide the respective optical system members in the optical axis direction so as to draw a trace, and the plurality of optical system members. An urging member that presses the guide portion of the cam member in a direction parallel to the optical axis direction is provided, and the plurality of optical system members are guided by the cam member by the guide portion of the cam member and the urging member. The guide portion of the cam member can be pressed or changed to a non-pressed state in accordance with the first region and the second region of the portion, or the pressing force on the guide portion is configured to be variable. It is characterized by having.

In the optical device having such a configuration, the regulating means is provided only in an area (focus adjustment area) in which backlash generated between the optical system member and the guide portion of the cam member needs to be removed in terms of optical performance. Acts so as to press the optical system member against the guide portion of the cam member in a direction parallel to the optical axis direction, and does not work in other areas (magnification switching area) or reduces the pressing force to reduce the optical force. It functions to reduce the frictional force generated between the system member and the guide portion of the cam member, and to reduce the driving load of the cam member.

Further, the optical device of the present invention for achieving the above-mentioned second object is: [3]: a plurality of optical system members movable in the optical axis direction, and the plurality of optical system members are mutually predetermined. A rotatable cam member having a guide portion having first and second regions alternately guiding the respective optical system members in the optical axis direction so as to draw a locus of the optical system members; and the plurality of optical system members. And a biasing member for pressing the guide member of the cam member in a direction parallel to the optical axis direction, and a guide portion of the cam member and the biasing member. Restricting means capable of changing to a state of being pressed or non-pressed on the guide portion of the cam member according to the first region and the second region of the portion, or of which the pressing force on the guide portion is variable, and the cam A driving unit for driving the member to rotate, and the regulating unit is configured to move the first member of the guide portion of the cam member. Control means for controlling the driving of the driving means by changing the driving frequency in accordance with the pressing force when pressing the plurality of optical system members on the area and the second area is provided.

In the optical device having such a configuration, the control means controls the pressing when the restricting means presses the optical system member against the first area and the second area of the guide section of the guide section of the cam member. The driving frequency of the driving unit is optimized according to the change in pressure, and the driving unit is driven.

The optical device according to the present invention, which achieves the above third object, is characterized in that in the above [1], [2] or [3], [4]: the regulating means is a guide portion of the cam member. Is the first
The optical system includes a region for changing the focal length of the optical system member and a region for performing the focusing operation of the optical system member as a second region and a second region. The pressing force F1 when the member is present and the pressing force F2 when the optical member is present in a region where the optical member performs the focusing operation are configured to satisfy a relationship of F2> F1 ≧ 0. It is characterized by.

In the optical device having such a configuration, the restricting means includes an area where the optical system member performs a focusing operation (focus adjustment area).
, The backlash between the optical system member and the guide portion of the cam member is removed by the pressing force F2 so as to enhance the optical performance, and the optical system member changes the focal length (magnification switching). In the range (1), the pressing force F1 is smaller than the pressing force F2 to prevent the driving load of the cam member from increasing.

Further, in the optical device of the present invention, particularly in the above [4], [5]: the guide portion of the cam member constituting the regulating means has an area for changing the focal length of the optical system member. The optical system member is formed so that the distance from the optical axis is larger than the region where the focusing operation of the optical system member is performed, and in the above [1], [2] or [3], ]: It is characterized in that a compression spring, a tension spring, a leaf spring or the like is used as an urging member constituting the regulating means.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical device according to the present invention will be described in more detail based on embodiments shown in the accompanying drawings. 1 to 7 show an optical device according to a first embodiment of the present invention, FIGS. 8 and 9 show a second embodiment of the optical device according to the present invention, and FIGS.
12 shows a third embodiment of the optical device according to the present invention, and FIG.
FIG. 13 shows an optical device according to a fourth embodiment of the present invention.

[First Embodiment] FIG. 1 is a cross-sectional view of a lens barrel of a camera or the like to which an optical device according to the present invention is applied, and a block diagram of main components. In FIG. 1, reference numeral 1 denotes a first lens group including a convex lens, 2 denotes a first lens holder that holds a first lens group, 3 denotes a second lens group that includes a concave lens, and 4 denotes a second lens that holds a second lens group. Holder.

The first lens group 1 and the second lens group 3 include a known zoom photographing lens system (hereinafter, referred to as a photographing lens system).
The first lens group 1 operates along the trajectory of a first cam groove 6 a shown in FIG. 2 formed in a cam cylinder 6 described later, and the second lens group 3 is formed in the cam cylinder 6. It operates along the locus of the second cam groove 6b shown in FIG.

Reference numeral 5 denotes a straight groove cylinder fixed to a camera body (not shown). Cam collars 16 and 18, which will be described later, are slidably fitted to the rectilinear groove cylinder 5, respectively, and are fitted to the optical axis O.
A groove 5a for guiding in the A direction is formed. The outer peripheral portions of the first lens holder 2 and the second lens holder 4 are slidably fitted to the inner diameter portion of the rectilinear groove cylinder 5, respectively, and are held by the lens holders 2, 4. The lens holders 2 and 4 are guided so as to prevent the optical axis OA of the first lens group 1 and the second lens group 2 from shifting.

Reference numeral 6 denotes a cam barrel mounted on a camera body (not shown) so as to be rotatable around the optical axis OA of the photographing lens systems 1 and 3. At the inner peripheral portion of the cam cylinder 6, the first
A first cam groove 6a in which a later-described first cam collar 16 of the lens holder 2 is slidably fitted, and a second cam groove in which a later-described second cam collar 18 of the second lens holder 4 is slidably fitted. 6b are formed.

Reference numeral 7 denotes a drive gear. This drive gear 7
It is rotatably attached to a camera body (not shown) by shaft portions 7a and 7b. In the drive gear 7, a gear portion 7c provided on an outer peripheral portion is meshed with a gear portion 6c formed on an outer peripheral portion of the cam cylinder 6, and the cam cylinder 6 is rotated around shafts 7a and 7b to rotate the cam cylinder 6. It is rotated around the optical axis OA.

Reference numeral 8 denotes a known step motor. The step motor 8 has an output shaft (not shown) meshed with a gear portion 7c of the drive gear 7 via a gear (not shown), and rotates the drive gear 7 by rotation of the output shaft. As the step motor 8, one shown in FIG. 6 is used as an example. The details of the step motor 8 will be described later.

Numeral 9 denotes a cam position detecting means for detecting the rotational position of the cam cylinder 6, which comprises a known potentiometer, for example. If a potentiometer is used as the cam position detecting means 9, a resistance value corresponding to the rotational position of the cam cylinder 6 can be detected. According to the cam position detecting means 9 using a potentiometer, the first lens group 1 is detected by detecting a resistance value corresponding to the rotational position of the cam barrel 6.
And the position of the second lens group 3 can be known.

Reference numeral 10 denotes a motor drive circuit for driving the step motor 8. The motor drive circuit 10 has a first drive mode and a second drive mode to be described later when the step motor 8 is driven, and these modes can be selectively used.

Reference numeral 11 denotes a control circuit composed of a microcomputer or the like and controls the sequence of the entire apparatus. Reference numeral 12 denotes exposure control means including a known shutter mechanism (not shown) and a known exposure control circuit (not shown). , 13 are known distance measuring means for measuring the distance to the subject.

Reference numeral 14 denotes a zoom switch for selecting the focal length of the photographing lens systems 1 and 3. The zoom switch 14 may be a known switch, and does not limit the present invention. As the zoom switch 14, for example, a potentiometer or the like can be employed. In this case, the control circuit 11 drives the step motor 8 to rotate the cam cylinder 6 to a desired position according to the resistance value output from the potentiometer.

Reference numeral 15 denotes a release switch. When the release switch 15 is closed, the camera is released.

Reference numeral 16 denotes a first cam collar, as shown in FIG. 3, whose inner diameter portion 16a is rotatable in the circumferential direction by a pin 2a projecting radially outward of the lens barrel from the first lens holder 2. The pin 2a is fitted so as to be slidable in the axial direction. The first cam collar 16 is engaged with the first cam groove 6a of the cam cylinder 6, and has an outer peripheral portion 16a.
c is slidably fitted with the groove 5 a of the rectilinear groove cylinder 5, and the tapered portion 16 b at the tip is engaged with the tapered portion of the first cam groove 6 a of the cam cylinder 6.

Reference numeral 17 denotes a first compression spring. The first compression spring 17 is disposed between the first cam collar 16 and the first lens holder 2, and presses the first cam collar 16 radially outward of the lens barrel.

Thus, the pin 2 of the first lens holder 2
The first cam collar 16 rotatably supported by a,
With the first compression spring 17 being pushed radially outward of the lens barrel, the first cam groove 6a is rotated and moved by frictional force in the first cam groove 6a following the rotation of the cam barrel 6. . At this time, the first cam is formed by a component force of a pressing force (pressing force) by which the tapered portion 16b is pressed against the first cam groove 6a by the first compression spring 17, that is, a horizontal component force acting in a direction parallel to the optical axis OA. The backlash generated between the groove and the groove 6a is removed.

Numeral 18 denotes a second cam collar, as shown in FIG. 3, whose inner diameter portion 18a is rotatable in the circumferential direction by a pin 4a projecting radially outward of the lens barrel from the second lens holder 4. The pin 4a is fitted so as to be slidable in the axial direction. The second cam collar 18 is engaged with the second cam groove 6 b of the cam cylinder 6, and has an outer peripheral portion 18.
c is slidably fitted in the groove 5a of the rectilinear groove tube 5, and the tapered portion 18b at the tip is engaged with the tapered portion of the first cam groove 6b of the cam tube 6.

Reference numeral 19 denotes a second compression spring. The second compression spring 19 is disposed between the second cam collar 18 and the second lens holder 4, and presses the second cam collar 18 radially outward of the lens barrel.

The pin 4 of the second lens holder 4
The second cam collar 18, which is rotatably supported by a,
With the second compression spring 19 pushed radially outward of the lens barrel, the second cam groove 6b rotates and moves in the second cam groove 6b by frictional force following the rotation of the cam barrel 6. . At this time, the second cam is formed by a component force of a pressing force (pressing force) in which the tapered portion 18b is pressed against the second cam groove 6b by the second compression spring 19, that is, a horizontal component force acting in a direction parallel to the optical axis OA. The backlash generated between the groove and the groove 6b is removed.

Next, the first cam groove 6a and the second cam groove 6b of the cam cylinder 6 will be described with reference to FIG. FIG. 2 shows the first cam groove 6 a and the second cam groove 6 at the rotational position of the cam cylinder 6.
The locus of b is shown.

In FIG. 2, when the cam barrel 6 is at a position of 0 °, the taking lens system including the first lens group 1 and the second lens group 3 is in a wide (WIDE) zoom position.
In addition, it is in a state of focusing on an infinite distance.

During the rotation of the cam barrel 6 from 0 ° to 30 °, that is, in the range of A1, the magnification of the photographing lenses 1 and 3 does not change, and the focus is changed to the wide state.
The lens focuses on the closest distance at the position.

When the cam barrel 6 is located at a position of 60 °, it becomes a zoom position having a focal length slightly longer than the wide position and is in a state of focusing on an infinite distance. That is, only the focal length is changed in the range of B1.

While the cam barrel 6 is rotating from 60 ° to 90 °, that is, the range of A2 is the same as the range of A1, the magnification of the photographing lens systems 1 and 3 is not changed, and the focal length is maintained. The focus is changed, and the lens is brought into a state in which the lens focuses at the closest distance at the position of 90 °.

As in the range of B1, the cam cylinder 6 is 120
At the position of °, the zoom position of the photographing lens system is further changed to the long focal length side, and the state of focusing on an infinite distance is set.

In the range of 120 ° to 150 °, that is, in the range of A3 in the drawing, the magnification of the photographing lens systems 1 and 3 is not changed in the range of A1 in the same manner as in the range of A1.変 更 The focus is changed, and the lens focuses at the closest distance at the position of 150 °.

Further, the cam barrel changes the photographing lens to the most telephoto zoom position at the position of 180 °,
In addition, focus is set to an infinite distance.

In the range of 180 ° to 210 °, that is, in the range of A4 in the drawing, the magnification of the photographic lens systems 1 and 3 is not changed and the focal length is changed without changing the focal length as in the range of A1. Then, at a position of 210 °, the lens is brought into a state in which the lens focuses on the closest distance.

As described above, the first cam groove 6a and the second
The cam groove 6b, as shown in FIG.
Areas (focus adjustment areas) A1, A2, A3, and A4 for performing a focusing operation of the photographing lens system including the zoom lens and the second lens group 3.
And the cam area (magnification switching area) B1 for changing the focal length
B2 and B3 are alternately and continuously provided.

The first cam groove 6a and the second cam groove 6b are provided with cam areas (focus adjustment areas) A1, A2, A3, and A4 for performing the above-described focusing operation and cam areas for changing the focal length. (Magnification switching area) B1, B2, B3 and optical axis OA
Distance from is different. That is, as shown in FIG.
Cam areas (focus adjustment areas) A1 and A for performing a focusing operation
2, A3, A4, the first cam groove 6a of the cam cylinder 6
And the distance of the second cam groove 6b from the optical axis OA is R1, but a cam area (magnification switching area) B for changing the focal length.
In most regions 1, B2 and B3, as shown in FIG. 4, the distance between the first cam groove 6a and the second cam groove 6b of the cam cylinder 6 from the optical axis OA is R2. Here, the relationship between the distance R1 and the distance R2 is R1 <R2.

The rotation of the cam barrel 6 causes the first cam collar 16 and the second cam collar 18 to move along the optical axis O.
When it comes to a position (magnification switching area) where the distance from A is R2, as shown in FIG. 4, the first cam collar 16 and the second cam collar 18 move the lens barrel by the difference distance Rt between the distance R1 and the distance R2. And the charging force of the first and second compression springs 17 and 19 is released by the difference distance Rt, so that the first cam collar 16 and the second cam collar 18 move the cam cylinder 6. 1 cam groove 6a
And, the pressing force against the second cam groove 6b is weakened. As a result, there is a possibility that the first lens holder 2 and the second lens holder 4 are moved in a direction parallel to the optical axis OA by a slight external force at a position (magnification switching area) where the distance from the optical axis OA is R2. However, the first cam groove 6a and the first cam collar 16 of the cam cylinder 6, and the second cam groove 6b and the second cam collar 18 of the cam cylinder 6 are provided.
The cam areas (magnification switching areas) B1, B2,
In B3, the driving load for rotating the cam cylinder 6 is small.

Incidentally, the cam areas (magnification switching areas) B1, B2, and B3 for changing the focal length are actually provided by the photographing lens system including the first lens group 1 and the second lens group 3 for exposing the film. Since the first lens group 1 and the second lens group 3 are not used during the operation, the first lens group 1 and the second lens group 3 do not accurately follow the corresponding first cam groove 6a and the second cam groove 6b of the cam cylinder 6 due to backlash or the like. Even if you move to, there is no obstacle in practical use.

Further, the first cam collar 16 and the second
When the cam collar 18 comes to a position (focus adjustment area) where the distance from the optical axis OA is R1 due to the rotation of the cam barrel 6, as shown in FIG. 3, the first cam collar 16 and the second cam collar 18 have the above-mentioned difference. The first and second compression springs 1 move radially inward of the lens barrel by the distance Rt.
The charging power of 7, 19 is sufficiently secured. For this reason, the tapered portion 1 of the first cam collar 16 and the second cam collar 18
6b, 18b are pressed against the corresponding first cam groove 6a and second cam groove 6b with a sufficiently strong force, so that the backlash between the first cam collar 16 and the first cam groove 6a,
And, the backlash between the second cam collar 18 and the second cam groove 6b is completely removed. As a result, the first lens holder 2 and the second lens holder 4 move the optical axis OA.
At a position where the distance from the lens is R1 (focus adjustment area), it is not displaced in a direction parallel to the optical axis OA due to a slight external force, and accurately moves along the first cam groove 6a and the second cam groove 6b of the cam cylinder. As a result, the optical performance of the taking lens system including the first lens group 1 and the second lens group 3 is sufficiently ensured.

Here, referring to FIG. 5, the first and second compression springs in a cam area (focus adjustment area) for performing the above-described focusing operation and a cam area (magnification switching area) for changing the focal length. The operation of 17, 17 will be described in detail.

FIG. 5 shows the position of the bottom surface of the first cam groove 6a or the second cam groove 6b of the cam cylinder 6, with the horizontal axis representing the rotation angle. In FIG. 5, OA denotes an optical axis, and 0 ° to 30 °, 60 ° to 90 °, and 120 ° to 1 shown in FIG.
Each of the angle ranges of 50 ° and 180 ° to 210 ° is the optical axis OA.
The photographing lens systems 1 and 3 whose distance from
Areas (focus adjustment areas) A1 and A for performing the focusing operation of
2, A3, A4, and 30 shown in FIG.
° to 60 °, 90 ° to 120 ° and 150 ° to 180 °
The angle ranges correspond to cam areas (magnification switching areas) B1, B2, and B3 in which the distance from the optical axis OA is R2 and the focal length of the photographic lens systems 1 and 3 is changed.

Thus, the first and second compression springs 17, 19 are provided in the cam areas (focus adjustment areas) A1, A
As shown in FIG. 3, the first cam collar 16 and the second cam collar 18 are pressed against the corresponding first cam groove 6a and second cam groove 6b of the cam cylinder 6 in the respective angular ranges corresponding to 2, 2 and A4. The pressing force acts to obtain the pressing force F2 sufficiently charged with the pressing force. However, in each angular range corresponding to the cam regions (magnification switching regions) B1, B2, and B3, as shown in FIG. A pressing force F1 for pressing the first cam collar 16 and the second cam collar 18 against the corresponding first cam groove 6a and the second cam groove 6b of the cam cylinder 6 with a force smaller than the pressing force F2 of the (focus adjustment area). Works. Therefore, the relationship between the pressing force F1 and the pressing force F2 is F2> F1.

As described above, in each angle range corresponding to the cam areas (magnification switching areas) B1, B2, and B3,
As another method of weakening the pressing force of the first and second compression springs 17 and 19, the first cam collar 16 and the second cam collar 18 are connected to the corresponding first cam groove of the cam cylinder 6 by further increasing the distance R2. 6a and the second cam groove 6b
Even if it is not pressed against the target, the initial purpose can be sufficiently achieved. In the case of such a configuration, the relationship between the pressing force F1 and the pressing force F2 is F2> F1 ≧ 0.

Next, the step motor 8 will be described in detail with reference to FIG. In the present embodiment, a step motor that has been disclosed by the invention of Japanese Patent Application Laid-Open No. 5-336729 is used as the step motor.

The outline of the configuration of the stepping motor disclosed in the above publication is as follows. A cylindrical rotor composed of a permanent magnet magnetized in a radial direction, and a plurality of magnetic pole portions arranged opposite to the outer periphery of the rotor are described. In a step motor having a plurality of stators having, and coils arranged to excite each of the stators, the rotor has a plurality of magnetized layers formed in its axial direction, and each magnetized layer has At least two magnetized portions, the magnetic pole portions of each adjacent magnetized layer are magnetized to opposite polarities, and the plurality of magnetic pole portions of each of the stators are different from each other in the axial direction of the rotor. Are arranged so as to face the magnetized portions of the above.

The structure of the stepping motor used in the present embodiment will be described below in detail. In FIG.
83 is a first stator and 84 is a second stator.

The rotor 82 is mounted on the main plate 81 so as to be rotatable about a shaft 82e as a center of rotation. The rotor 82 is magnetized in the radial direction, that is, in the radial direction that divides the circumferential direction into two. Further, the rotor 82
The magnetized layers 82a, 82b, 8 are divided into two layers in the axial direction.
2c and 82d are provided respectively. Each magnetized layer 82
Reference numerals a, 82b, 82c, and 82d denote circumferentially adjacent portions, for example, the magnetized portions 82a and 82b are magnetized with opposite polarities, and adjacent portions of the upper and lower magnetized portions, for example, magnetized portions. The magnetic parts 82a and 82c are magnetized in opposite polarities. That is, for example, the magnetized portion 82a is
The portion 2b is magnetized to the S pole, the portion 82c is magnetized to the S pole, the portion 82d is magnetized to the N pole, and so on.

The first stator 83 includes magnetic pole portions 83a, 83
b, and these magnetic pole portions 83a, 83b
Is fixed to the base plate 81 so as to be adjacent to the base plate 81. On the other hand, the second stator 84 has magnetic pole portions 84a and 84b, and the magnetic pole portions 84a and 84b are fixed to the base plate 81 at a position opposite to the first stator 83 so as to be adjacent to the rotor 82. I have.

First stator 83 and second stator 84
Are configured such that their magnetic pole portions 83a, 83b, 84a, 84b overlap in the axial direction of the rotor 82, respectively. The magnetic pole portion 83a of the first stator 83 and the magnetic pole portion 84a of the second stator 84 face a cylindrical portion including the upper magnetized portions 82a and 82b of the rotor 82. The magnetic pole part 83b of the 83 and the magnetic pole part 84b of the second stator 84 face the cylindrical part including the magnetized parts 82c and 82d on the lower side of the rotor 82.

Reference numeral 85 denotes a coil for exciting the first stator 83, and reference numeral 86 denotes a coil for exciting the second stator 84.

The step motor 8 constructed as described above
Is configured to rotate stepwise by sequentially switching the energization of the coil 85 and the coil 86 between normal and reverse.

Next, the operation of the control circuit 11 will be described with reference to the flowchart shown in FIG.

In step 1, the zoom switch 14
The set value of is detected. That is, the resistance value of the zoom switch 14 composed of a potentiometer is detected, and the input value of the zoom position to be detected is detected.

In step 2, the value of the cam position detecting means 9 comprising a potentiometer is detected to detect the current position of the cam barrel 6, that is, which zoom position the photographing lens systems 1 and 3 are at.

In step 3, it is determined whether or not the set value of the zoom position detected in step 1 is the same as the current zoom position of the photographing lens systems 1 and 3 detected in step 2. If they are the same, proceed to step 5; if they are different, proceed to step 4.

In step 4, the motor drive circuit 10
, The step motor 8 is driven. At this time, at the position where the first cam collar 16 and the second cam collar 18 are engaged with the corresponding first cam groove 6a and second cam groove 6b of the cam cylinder 6, the first cam groove 6a and the second cam When the distance of the groove 6b from the optical axis OA is R1, the pressing force of the first and second compression springs 17, 19 is large,
Each cam collar 16, 18 and each cam collar 16, 18
The frictional force generated between each of the cam grooves 6a and 6b corresponding to increases. Therefore, since the driving load of the cam cylinder 6 is increased, the stepping motor 8 is controlled to be driven at a low driving frequency which is the first driving mode in which the driving output of the stepping motor 8 is large. Prevent out-of-step.

The first cam collar 16 and the second cam collar 18 are connected to the corresponding first cam groove 6a and the second
The first cam groove 6 is engaged with the cam groove 6b.
When the distance from the optical axis OA of the second cam groove 6a and the second cam groove 6b is R2, the pressing force of the first and second compression springs 17, 19 is small, and the cam collars 16, 18 and the first cam groove 6a , The frictional force generated between the second cam grooves 6b is reduced. Therefore, since the driving load of the cam cylinder 6 is reduced, the stepping motor 8 is controlled to be driven by a high-frequency driving frequency which is the second driving mode in which the driving output of the stepping motor 8 is small. Drive quickly.

If it is determined in step 5 that the zoom position set by the zoom switch 14 in step 3 is the same as the current zoom position of the photographing lens systems 1 and 3, the step motor 8 is moved. Since there is no need, the operation of the motor drive circuit 10 is not performed. However, if the zoom position set by the zoom switch 14 is different from the current zoom position of the photographing lens systems 1 and 3, the step motor 8 is driven in step 4 as described above, and step 2 is performed again. When the zoom position set by the zoom switch 14 and the current zoom position of the photographing lens systems 1 and 3 become the same, the process returns to step 3 via the motor drive circuit 10 to step motor 8. To stop driving.

At step 6, the release switch 1
It is detected whether or not 5 is turned on. If it is turned on, the process proceeds to step 7, and if not, the process returns to step 1.

In step 7, the distance measuring means 13 is driven to measure the distance to the subject.

In step 8, the motor drive circuit 10
, The stepping motor 8 is driven, and the cam barrel 6 is rotated to perform the focusing operation of the photographing lens systems 1 and 3. Since the position of the cam cylinder 6 at this time is a region where the driving load is large,
The step motor 8 is driven at a low drive frequency, which is the first drive mode described above, to prevent the step motor 8 from stepping out.

In step 9, the value of the cam position detecting means 9 comprising a potentiometer is detected.

In step 10, it is detected whether or not the cam cylinder 6 has come to a position corresponding to the distance to the subject detected in step 7, and if it is detected that the cam cylinder 6 has been positioned at that position, step The process proceeds to step 11 and returns to step 8 if the cam cylinder 6 has not been positioned yet.

In step 11, the photographing lens systems 1 and
3 is positioned at the in-focus position.
Then, the rotation of the step motor 8 is stopped via 0. At this time,
The energization of the coils 85 and 86 of the step motor 8 is not interrupted, and the energization of the coils 85 and 86 is continued while the applied voltage of the micro step drive is maintained so that the rotor 82 is held at that position.

In step 12, the exposure control means 12
To operate an unillustrated shutter to perform an exposure operation on an unillustrated film. Thereafter, the power supply to the step motor 8 may be completely cut off.

In step 13, after that, the normal camera operation, for example, one frame advance of the film is performed.

[Second Embodiment] Next, a second embodiment of the optical device according to the present invention will be described with reference to FIGS. In the second embodiment, the first lens holder 2 is fixed to the first cam groove 6a of the cam cylinder 6 and the pin 2 of the first lens holder 2 by using an urging ring 4 and a tension spring 21 described later.
a, and the cam cylinder 6
In addition to the above-described structure, the frictional force generated between the first cam groove 6a and the pin 2a of the first lens holder 2 is suppressed from increasing and the driving load for rotating the cam barrel 6 is reduced. The configuration is similar to that of the first embodiment.

FIG. 8 is a sectional view of the lens barrel of the optical apparatus, showing a state where the first lens holder 2 and the second lens holder 4 are in the cam area A4 shown in FIG. FIG. 9 is a developed view of the cam barrel 6 of the lens barrel shown in FIG.

As shown in FIG. 8, the first lens holder 2
The pin 2a is slidably fitted in the first cam groove 6a of the cam cylinder 6 with a small gap. In the second lens holder 4, the pin 4 a is slidably fitted in the second cam groove 6 b of the cam barrel 6. Further, the pin 2a of the first lens holder 2 and the pin 4a of the second lens holder 4 are slidably fitted in the grooves 5a of the rectilinear groove cylinder 5, respectively.

Reference numeral 20 denotes an urging ring, the outer periphery of which is slidably fitted to the inner diameter of the straight groove tube 5 and held so as to be slidable in a direction parallel to the optical axis OA. The biasing ring 20 has a pin 20a protruding from an outer peripheral portion thereof in a radial direction of the lens barrel portion and slidably fitted in the groove 5a of the rectilinear groove tube 5 in a direction parallel to the optical axis OA. 6 cam groove 6c
And slidably fitted.

Reference numeral 21 denotes a tension spring disposed between the urging ring 20 and the first lens holder 2 and acting to pull the urging ring 20 and the first lens holder 2 toward each other in a direction parallel to the optical axis OA. is there.

The first lens holder 2 and the urging ring 2
0 denotes a gap L between the left end face 2b of the first lens holder 2 and the right end face 20b of the urging ring 20, as shown in FIG.
2 are formed. That is, when the relative position of the urging ring 20 and the first lens holder 2 approaches the gap L2, the right end surface 20b of the urging ring 20 and the left end surface 2b of the first lens holder 2 come into contact with each other and may be further approached. It is configured so that it cannot be done.

As shown in FIG. 9, the cam groove 6c of the cam cylinder 6 has a cam area (focus adjustment area) in which the focusing operation of the photographing lens systems 1 and 3 is performed, that is, A1, A2, A3 and A4. The left end face is formed so as to be located at a position separated by a gap L3 from the right end face of the first cam groove 6a.

In such a cam area (focus adjustment area), as described above, a gap L2 is formed between the first lens holder 2 and the urging ring 20, and the urging force (tensile force) of the tension spring 21 is formed. ), The pin 2a of the first lens holder 2 is urged toward the right end face of the first cam groove 6a, and moves along the right end face with the rotation of the cam barrel 6 in this state. As a result, the backlash between the first cam groove 6a and the pin 2a is eliminated, and the first lens group 1 is driven with a constant movement locus.

The cam groove 6c of the cam cylinder 6 has a left end face in a cam area (magnification switching area) B1, B2, or B3 in which the focal length of the photographing lens systems 1 and 3 is changed. In most regions, the gap L is larger than the right end face of the first cam groove 6a.
It is formed so as to be located at a distance of one. Here, L1 is L3-L2> L1.

In such a cam area (magnification switching area), the left end surface 2b of the first lens holder 2 and the urging ring 2
0 abuts against the right end face 20b of the first lens holder 2 by the urging force (tensile force) of the tension spring 21 so that the pin 2a of the first lens holder 2 is not pressed against the right end face of the first cam groove 6a to rotate the cam barrel 6. Accordingly, it moves along the right end face. As a result, an increase in the frictional force generated between the first cam groove 6a and the pin 2a is suppressed, and the driving load for rotating the cam cylinder 6 is reduced.

Although the backlash between the first cam groove 6a and the pin 2a is not removed in the cam area (magnification switching area), the cam area (magnification switching area) has a focal length as described above. Since this is a region for changing, there is no effect on optical performance in actual photographing.

[Third Embodiment] Next, FIG. 10 and FIG.
A third embodiment of the optical device according to the present invention will be described based on FIG. In the third embodiment, the first lens holder 2 is fixed to the first cam groove 6a of the cam barrel 6 and the pin 2 of the first lens holder 2 by using a pressing ring 22 and a leaf spring 23 described later.
a, and the cam cylinder 6
In addition to suppressing the generation of a frictional force between the first cam groove 6a and the pin 2a of the first lens holder 2, the driving load for rotating the cam cylinder 6 is reduced.
The configuration is the same as that of the embodiment.

FIG. 10 is a cross-sectional view of the lens barrel of the optical device, showing a state where the first lens holder 2 and the second lens holder 4 are in the cam area A4 shown in FIG. FIG. 11 is a developed view of the cam barrel 6 when the lens barrel shown in FIG. 10 is viewed from the outer peripheral surface side.

As shown in FIG. 10, the pin 2a of the first lens holder 2 projects to the outer peripheral portion of the cam cylinder 6 through the first cam groove 6a of the cam cylinder 6.

Reference numeral 22 denotes a pressing ring fitted to the outer peripheral portion of the cam cylinder 6 so as to be slidable in a direction parallel to the optical axis OA.
As shown in FIG. 11, the pressing ring 22 has an elongated hole 22a extending in the direction of the optical axis OA. The elongated hole 22a slides on a pin 6e provided in the cam cylinder 6 only in a direction parallel to the optical axis OA. It is movably fitted to prohibit the movement of the cam cylinder 6 in the rotation direction and regulate the movement amount in the direction parallel to the optical axis OA.

Reference numeral 23 denotes a leaf spring, one end 23a of which is fixed to the cam barrel 6 and the other end 23b abuts against the pressing ring 22 to apply a leftward urging force to the pressing ring 22.

On the left end face side of the pressing ring 22,
Projections 22b, 22c, 22d and 22e slightly projecting in the first cam groove 6a in the optical axis OA direction are formed. These protrusions 22b, 22c, 22d, 22e
Corresponds to cam areas (focus adjustment areas) in which the focusing operations of the photographing lens systems 1 and 3 are performed, that is, A1, A2, A3, and A4.

The protrusions 22b, 22c, 22d, 22
When the pin 2a of the first lens holder 2 is in the cam area (focus adjustment area) A1, A2, A3, A4, the pin 2a comes into contact with the pin 2a and the pin 2a is moved to the first cam of the cam barrel 6. The first cam groove 6 is pressed against the left end face of the groove 6a.
and acts to eliminate backlash between the pin a and the pin 2a.

Also, the protrusions 22b, 22c, 22
Reference numerals d and 22e denote cam areas (magnification switching areas) in which the focal lengths of the photographing lens systems 1 and 3 are changed, that is, B1, B2, and B3.
In this case, a non-contact state in which the pin 2a of the first lens holder 2 does not come into contact with the first lens holder 2 so that the driving load for rotating the cam barrel 6 does not increase.

[Fourth Embodiment] Next, FIG. 12 and FIG.
A fourth embodiment of the optical device according to the present invention will be described based on FIG. In the fourth embodiment, the pin 2a of the first lens holder 2 and the first cam collar 16 are connected so as to form a gap n in the axial direction, and the first cam groove 6a of the cam cylinder 6 is
The configuration is the same as that of the above-described first embodiment, except that the generation of the frictional force between the pin 2a of the lens holder 2 and the driving load for rotating the cam barrel 6 are reduced. I have.

FIG. 12 shows the first lens holder 2 of the first embodiment in the cam area where the focusing operation of the taking lens system is performed, that is, the cam area (focus adjustment area) A1, referred to in the first embodiment. FIG. 4 is a detailed cross-sectional view of the first cam collar 16 and the first cam groove 6a when located in A2, A3, and A4. FIG.
FIG. 13 is an operation explanatory view of the first cam collar 16 and the first cam groove 6a shown in FIG.

As shown in FIG. 12, the pin 2a of the first lens holder 2 has a head 2b with a large diameter at the tip, and a cam area (focus adjustment) for performing the focusing operation of the photographing lens systems 1 and 3 (Area) The first cam collar 16 is held in the state A1, A2, A3, A4 separated from the head 2b by a gap n.
The gap n is set to be smaller than the difference distance Rt of the first embodiment. Thus, when the first lens holder 2 is located in the cam area (magnification switching area) B1, B2, B3, that is, at a position where the distance of the first cam groove 6a from the optical axis OA is R2 (= R1 + t). As shown in FIG. 13, the first cam collar 16 and the first cam groove 6a are in a non-contact state to have a gap, and
The cause of the frictional force between the cam collar 16 and the first cam groove 6a can be eliminated, and the driving load for rotating the cam cylinder 6 can be reduced.

Also, the first lens holder 2 is
When returning to the state of (1), the compression spring 17 needs to be recharged. However, since the gap n is smaller than the difference distance Rt, the distance for recharging the compression spring 17 is shorter than in the first embodiment. The driving load for rotating the cam cylinder 6 is smaller than in the first embodiment.

[0105]

As described above, in the optical device according to the present invention, the regulating means comprising the guide portion of the cam member and the biasing member is provided with the back member formed between the optical system member and the guide portion of the cam member. The lash acts only in the area where the optical performance needs to be removed (focus adjustment area), and presses the optical system member against the guide portion of the cam member in a direction parallel to the optical axis direction. Since the frictional force generated between the optical system member and the guide portion of the cam member is suppressed as a function or by reducing the pressing force, backlash of the optical system member can be removed in the focus adjustment area, and The drive load of the cam member can be reduced in the magnification switching range.

[0106] Further, the regulating means comprising the guide portion of the cam member and the biasing member is provided in the first region of the guide portion of the cam member and the second region.
The driving means is controlled by changing the driving frequency of the driving means by the control means in accordance with the pressing force when pressing the optical system member in the area of (2). (Switching area), the driving frequency of the driving means can be optimized and the driving means can be driven in accordance with the change of the pressing force when pressing the optical system member, and therefore, the driving operation of the cam member for focus switching Can be accelerated.

The relationship between the pressing force F1 when the optical system member is in the magnification switching region of the guide portion of the cam member and the pressing force F2 when the optical system member is in the focus adjustment region of the guide member is F2> F1 ≧ 0. Since the above-described restricting means is configured so that the backlash can be removed in the region where the focusing operation is performed on the optical system member (focus adjustment region), the region where the focal length is changed (magnification switching region) Thus, it is possible to prevent the driving load of the cam member from increasing.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a lens barrel of a first embodiment of an optical device according to the present invention and a block diagram of main components.

FIG. 2 shows a first cam groove and a second cam groove of the cam cylinder of the first embodiment.
It is a development view showing the locus of a cam groove.

FIG. 3 is a detailed cross-sectional view of the first embodiment when the first lens group and the second lens group are located in the focus adjustment areas of the corresponding first cam groove and second cam groove of the cam barrel. .

FIG. 4 is a detailed cross-sectional view of the first embodiment when the first lens group and the second lens group are located in the variable magnification switching area of the corresponding first cam groove and second cam groove of the cam barrel; It is.

FIG. 5 is a developed view showing the position of the bottom surface of the first cam groove or the second cam groove of the cam cylinder of the first embodiment, with the horizontal axis representing the rotation angle.

FIG. 6 is a schematic perspective view of a drive unit of the step motor according to the first embodiment.

FIG. 7 is a flowchart illustrating an operation of the control circuit according to the first embodiment.

FIG. 8 is a sectional view of a lens barrel of an optical device according to a second embodiment of the present invention.

FIG. 9 is a development view of a cam barrel of the lens barrel of the second embodiment.

FIG. 10 is a sectional view of a lens barrel of an optical device according to a third embodiment of the invention.

FIG. 11 is a development view of the cam barrel when the lens barrel section of the third embodiment is viewed from the outer peripheral surface side.

FIG. 12 is a detailed cross-sectional view illustrating a fourth embodiment of the optical apparatus according to the present invention, in which the first lens group is located in the focus adjustment area of the first cam groove of the cam barrel.

FIG. 13 is an explanatory diagram of the operation when the first lens group of the fourth embodiment is located in the variable power switching area of the first cam groove of the cam barrel.

FIG. 14 is a schematic diagram of a main part of a magnification switching operation and a focus adjustment operation in a conventional optical device.

FIG. 15 is an explanatory diagram showing a movement locus of each lens group of the conventional optical device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st lens group (optical system member) 3 2nd lens group (optical system member) 6 Cam cylinder (cam member) 6a, 6b Cam groove (guide part) 8 Step motor (drive means) 11 Control circuit (control means) 16, 18 Cam collar 17, 19 Compression spring (biasing member) 21 Tension spring (biasing member) 23 Leaf spring (biasing means) A1, A2, A3, A4 Focus adjustment area B1, B2, B3 Magnification switching area

Claims (6)

[Claims] 1. An optical system member movable in an optical axis direction, and a first region and a second region for guiding the optical system member in the optical axis direction such that the optical system member draws a predetermined trajectory. A rotatable cam member having alternately provided guide portions, and a biasing member for pressing the optical system member against the guide portion of the cam member in a direction parallel to the optical axis direction, the guide portion of the cam member; By the urging member, the optical system member is pressed against the guide portion of the cam member in accordance with the position of the cam member at the guide portion,
Alternatively, an optical device characterized in that the optical device constitutes a restricting means capable of changing to a non-pressed state or a variable pressing force to the guide portion. 2. A plurality of optical system members movable in the optical axis direction, and a first guide for guiding the respective optical system members in the optical axis direction such that the plurality of optical system members draw a predetermined trajectory with respect to each other. Rotatable cam member having a guide portion having alternately a second region and a second region, and a biasing member for pressing the plurality of optical system members against the guide portion of the cam member in a direction parallel to the optical axis direction. The plurality of optical system members are guided by the guide portion of the cam member and the urging member in accordance with the first region and the second region of the guide portion of the cam member. An optical device comprising a regulating means capable of changing to a state of being pressed or non-pressed on a portion, or of having a variable pressing force on the guide portion. 3. A plurality of optical system members movable in an optical axis direction, and a first guide for guiding the respective optical system members in the optical axis direction such that the plurality of optical system members draw predetermined trajectories with respect to each other. Rotatable cam member having a guide portion having alternately a second region and a second region, and a biasing member for pressing the plurality of optical system members against the guide portion of the cam member in a direction parallel to the optical axis direction. And a plurality of optical system members each comprising a guide portion of the cam member and the urging member.
A restricting means capable of changing to a state of being pressed or non-pressed on the guide portion of the cam member or a variable pressing force on the guide portion according to the area and the second area, and rotating the cam member Drive means, and the control means sets the drive frequency to a drive frequency in accordance with the pressing force when the restricting means presses the plurality of optical system members against the first area and the second area of the guide portion of the cam member. An optical device, comprising: control means for changing and controlling driving. 4. The optical system according to claim 1, 2 or 3, wherein the guide section of the cam member has a first area and a second area where a focal length of the optical system member is changed as a first area and a second area. A region in which the focusing operation of the optical system member is performed, and a pressing force F1 when the optical system member is in the region where the focal length of the optical system member is changed, and a region in which the focusing operation of the optical system member is performed. The pressing force F2 when the optical member is present is F2>
An optical device characterized by being configured to satisfy a relationship of F1 ≧ 0. 5. The guide section of the cam member constituting the regulating means according to claim 4, wherein a region in which a focal length of the optical system member is changed is more light than a region in which the focusing operation of the optical system member is performed. An optical device, wherein the optical device is formed so as to have a large distance from an axis. 6. The optical device according to claim 1, wherein a compression spring, a tension spring, a leaf spring, or the like is used as an urging member constituting the restricting means.