JP2003098417A - Zoom lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a zoom lens barrel compact. SOLUTION: This zoom lens barrel is equipped with a fixed barrel 1, a guide barrel 2 supported by the fixed barrel 1 and having a guide groove, a front cam barrel 3 and a rear cam barrel 4 rotatably provided in the guide barrel 2, divided in front and rear in an optical axis direction and respectively having groove parts, lens groups for variable power 8 and 9 being two front and rear groups provided in the cam barrels 3 and 4, pins 16 and 18 fixed in the lens frames 15 and 17 of the lens groups 8 and 9 and engaged in the cam groove and the guiding groove, and a spring 14 energizing the cam barrel 3 in the optical axis direction. By providing a front cam pin 11 and a front cam guide groove 13 in the cam barrel 3 and the cam barrel 4, respectively, and engaging the cam pin 11 in the guide groove 13, the cam barrels 3 and 4 are coupled with each other, while the guide groove 13 has a part inclined in the optical axis direction, and the cam pin 11 is guided to move by the inclined part with the rotation of the cam barrel 4, whereby the positional relation between the lens groups 8 and 9 is set to a relation other than that due to the cam groove.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens barrel for moving a lens group in an optical axis direction by rotating a cam barrel having a cam groove formed therein.

[0002]

2. Description of the Related Art In a conventional zoom lens barrel, first and second groups of cam grooves are formed in a cam barrel, and pins fixed to the first and second groups of lens frames are engaged with the cam grooves. By rotating the cam barrel, the lens frame is moved in the optical axis direction to adjust the position of the lens group.

[0003]

By the way, in general, when the zoom lens barrel has a macro photography mode and a group relation other than the group relation from wide to tele is required, the cam groove is further lengthened. , Need to have a position.
For this reason, it is necessary to increase the outer diameter of the cam cylinder or increase the angle of the cam shape. When the outer diameter of the cam barrel is increased, the outer shape of the lens barrel is naturally increased. Further, when the cam angle is increased, the torque for driving the cam barrel to be increased becomes large, which requires a large reduction gear and a large motor, resulting in a large lens barrel. There's a problem.

An object of the present invention is to make the zoom lens barrel compact.

[0005]

In order to solve the above-mentioned object, the invention as set forth in claim 1 has a fixed barrel, a guide barrel supported by the fixed barrel and having a guide groove formed therein, and rotating in the guide barrel. A cam barrel freely provided with a guide portion, two front and rear lens groups for zooming provided in the cam barrel, and a member fixed to the lens frame of the zoom lens group and guided by the guide portion. An information desk,
And a biasing means for biasing the cam barrel in the optical axis direction, and by rotating the cam barrel around the optical axis, the guided portion moves along the guide groove to rotate the zoom lens group. In a zoom lens barrel that is moved in the optical axis direction without moving, the cam barrel is divided into two in the front and rear along the optical axis direction to guide the front and rear cam barrels as a front cam barrel and a rear cam barrel, respectively. The front cam barrel and the rear cam barrel are provided with a front cam pin and a rear cam barrel with a front cam guide groove, and the front cam pin engages with the front cam guide groove. While connecting the cylinder to each other, the front cam guide groove has an inclined portion that is inclined with respect to the optical axis direction, and the front cam pin is guided by the inclined portion and moves as the rear cam cylinder rotates, Change the position of the zoom lens group to a position other than the position related to the guide. It is characterized by a constant.

In the above structure, when the rear cam barrel is rotated, the front cam pin of the front cam barrel moves along the front cam guide groove of each rear barrel, whereby the front cam barrel moves in the optical axis direction. . For example, if the front cam barrel is moved forward in the optical axis direction, macro photography is possible. As described above, according to the above configuration, it is possible to realize a compact zoom lens barrel capable of macro photography without changing the outer diameter of the cam barrel or the angle of the cam shape.

According to a second aspect of the present invention, in the first aspect, during normal photographing, the front cam barrel is brought into close contact with the rear cam barrel by the biasing means, and the front cam barrel rotates integrally with the rear cam barrel. It is characterized by that.

The invention described in claim 3 is the invention according to claim 1 or 2.
In the above, the guide cylinder is provided with a stopper that restricts the rotation of the front cam cylinder, and during normal shooting, when the rear cam cylinder is rotated by a predetermined amount or more, the arm portion of the front cam cylinder having the front cam pin contacts the stopper. The front cam barrel is prevented from rotating in contact with the front cam barrel, and the front cam pin moves in one direction on the inclined portion to separate the front cam barrel from the rear cam barrel.

According to a fourth aspect of the present invention, in the third aspect, the guide cylinder is capable of abutting against the arm portion, a stopper different from the stopper is provided, and the front cam barrel is separated from the rear cam barrel. When the rear cam barrel is rotated in the reverse direction, the arm comes into contact with another stopper to prevent the front cam barrel from rotating, and the front cam pin moves in the opposite direction on the inclined portion, causing the front cam barrel to move backward. It is characterized by being closely attached to.

The invention described in claim 5 is the same as claim 1.
1 to 4, the guide portions of the front cam barrel and the rear cam barrel are formed in a shape that maintains a group relationship necessary for continuously varying the magnification from wide to tele under normal use conditions. It is characterized in that the variable magnification lens group forms a group relationship capable of macro photography by changing the positional relationship between the front cam barrel and the rear cam barrel during shooting. As for the positional relationship between the front cam cylinder and the rear cam cylinder during forward rotation, maintaining the relationship of the guide portion that continuously varies the magnification from the normal wide angle to the telescopic angle, and if the positional relationship is shifted and then the reverse rotation is performed, It is possible to have a relationship between the first group and the second group that enables macro photography at an arbitrary place.

According to a sixth aspect of the present invention, in any one of the first to fourth aspects, the guide portions of the front cam barrel and the rear cam barrel continuously vary the magnification from wide to tele under normal use. It is formed in a shape that maintains the group relationship necessary for this, and by changing the positional relationship between the front cam barrel and the rear cam barrel, the zoom lens group can have a lens configuration with a focal length other than wide to tele during normal shooting. It is characterized by taking. In this case as well, similar to the fifth aspect, it is possible to configure the positional relationship between the first group and the second group having a focal length other than the telephoto range from the wide range in the normal shooting at an arbitrary position.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

This embodiment is an example of a zoom lens barrel with a macro function. FIG. 1 is a sectional view of a main part of the zoom lens barrel during normal shooting, and FIG. 2 is a sectional view of a main part during macro shooting. is there. FIG. 3 shows the positional relationship between the front cam barrel and the rear cam barrel during normal shooting, and FIG. 4 shows the positional relationship between the front cam barrel and the rear cam barrel during macro shooting. 5 is a perspective view showing the positional relationship between the front cam barrel and the rear cam barrel during normal shooting, and FIG. 6 is a perspective view showing the positional relationship between the front cam barrel and the rear cam barrel during macro shooting. Further, FIG. 7 is a perspective view of the fixed barrel, and FIG. 8 is a perspective view of the guide barrel.

The fixed barrel 1 is fixed to a camera (not shown), and a cylindrical guide barrel 2 is provided inside the tip of the fixed barrel 1. Inside the guide cylinder 2, a front cam cylinder 3 and a rear cam cylinder 4 which are divided into two in the front and rear along the optical axis direction and have a cylindrical shape are provided. A pin 5 is fixed to the rear cam barrel 4, and the pin 5 penetrates a groove 6 formed in the guide barrel 2 in the circumferential direction and engages with a cam groove 7 formed in the fixed barrel 1. Then, when the rear cam barrel 4 is rotated, the pin 5 moves following the cam groove 7. At this time, the fixed cylinder 1
Is provided with a key groove 1A, and the guide tube 2 is provided with a key 2A fitted into the key groove 1A. When the pin 5 moves following the cam groove 7, the key 2A moves in the key groove 1A. The guide tube 2 moves in the optical axis direction while being prevented from rotating. As a result, the first group and the second group (the first group lens 8 and the second group lens 9) can be simultaneously moved in the optical axis direction.

The front cam barrel 3 is provided with arms 10 projecting outward at three locations along the circumferential direction on the side close to the rear cam barrel 4, and inside the arm 10 the front cam pin 11 is provided. Is fixed. Further, a space 12 into which the arm portion 10 is inserted is provided on the inner peripheral surface of the guide cylinder 2. on the other hand,
Front cam guide grooves 13 are formed on the rear cam barrel 4 near the front cam barrel 3 at three locations along the circumferential direction, and the front cam pins 11 engage with the front cam guide grooves 13. ing. As shown in FIG. 9, the front cam guide groove 13 includes an inclined portion 13A inclined with respect to the optical axis direction and an inclined portion 13A.
And a vertical portion 13B communicating with the optical axis direction and perpendicular to the optical axis direction. The vertical portion 13B may be an inclined portion 13C having an angle opposite to that of the inclined portion 13A as indicated by the chain double-dashed line in FIG.

On the front side of the front cam cylinder 3, between the guide cylinder 2 and
The front cam barrel 3 is provided with a spring 14 as a biasing means.
Is urged toward the rear cam barrel 4 by a spring 14. Further, inside the front cam barrel 3 and the rear cam barrel 4, a first group lens 8 and a second group lens 9 capable of zooming are installed respectively. The first group lens 8 is held by the lens frame 15,
A pin 16 is fixed to the lens frame 15. Similarly, the second group lens 9 is held by the lens frame 17, and the pin 18 is fixed to the lens frame 17. A substantially V-shaped cam groove 19 is formed in the front cam barrel 3 as shown in FIG. 3, and a substantially inverted V-shaped cam groove 20 is formed in the rear cam barrel 4 as shown in FIG. A linear guide groove 21 is formed in the guide tube 2 along the optical axis direction. Here, the cam grooves 19 and 20 configure a guide portion, and the pins 16 and 18 configure a guided portion.

The pin 16 penetrates the cam groove 19 of the front cam cylinder 3 to engage with the guide groove 21 of the guide cylinder 2, and the pin 18 penetrates the cam groove 20 of the rear cam cylinder 4 to guide the guide cylinder 2. The groove 21 is engaged. When the front cam barrel 3 and the rear cam barrel 4 rotate, the guide barrel 2 is prevented from rotating as described above, so that the pins 16 and 18 are guided and moved by the cam grooves 19 and 20. The front cam barrel 3 and the rear cam barrel 4 move in the optical axis direction. The moving range at this time depends on the rotation angles of the front cam barrel 3 and the rear cam barrel 4 and the shapes of the cam grooves 19 and 20. Although not shown in the figure, the zoom lens barrel according to the present embodiment is provided with a drive unit (motor) for rotationally driving the rear cam barrel 4.

In the zoom lens barrel having the above structure, W
When the focal length is continuously changed from "ide" (wide) to "tele" (this is called normal photographing), the front cam pin 11 is located at the end of the inclined portion 13A of the front cam guide groove 13 as shown in FIG. There is a spring 14 on the front cam cylinder 3
As a result, the front cam barrel 3 and the rear cam barrel 4 are in close contact with each other as shown in FIG. 3 or FIG. In this state, when the drive means rotates the rear cam barrel 4, the rotational force is transmitted to the front cam barrel 3 via the arm portion 10, and the front cam barrel 3 rotates integrally with the rear cam barrel 4. To do. The positional relationship between the first group and the second group at that time is shown in FIG.
It is as shown from storage to Tele.

The guide cylinder 2 has a front cam cylinder 3 as described above.
A space 12 for the arm portion 10 of the
During normal shooting from de to Tele, the arm 10 is in the space 12 and does not hit the guide tube 2.

As shown in FIG. 10, the guide tube 2 is provided with a stopper 25 inside the space 12 outside the Tele side and a stopper 26 outside the Wide side. Then, when the rear cam barrel 4 is further rotated from Tele, the arm portion 10 of the front cam barrel 3 is moved to the space 12
It hits the stopper 25 of the
Therefore, the front cam barrel 3 cannot rotate any more.
Further rotation causes the front cam pin 11 of the arm portion 10 to move from the inclined portion 13A of the front cam guide groove 13 to the vertical portion 13B. At this time, only the rear cam barrel 4 rotates, and the front cam barrel 3 receives the force from the front cam pin 11 when the front cam pin 11 moves along the inclined portion 13A of the front cam guide groove 13 to receive the optical axis. Move forward in the direction. As a result, the front cam barrel 2 is separated from the rear cam barrel 4. When the front cam pin 11 reaches the tip of the vertical portion 13B of the front cam guide groove 13, the rotation of the rear cam barrel 4 is stopped.

In the present embodiment, since the front cam guide groove 13 is provided with the vertical portion 13B, the front cam barrel 3 is displaced from the rear cam barrel 4 in the rotational direction and is separated from the rear cam barrel 4. And can be maintained stable.

Next, the rear cam barrel 4 is rotated in the reverse direction from the state of the stopper hit a so that the distance between the first lens group 8 and the second lens group 9 becomes optimal for macro photography, and the front cam barrel 3 and the rear cam barrel 3 are rotated. The position of the cylinder 4 is adjusted as shown in FIG. 4 or 6. This enables macro photography. It should be noted that the distance between the first lens group 8 and the second lens group 9 should be the optimum distance,
The shape of the front cam guide groove 13 of the rear cam barrel 4 is set.

Further, when returning from the state at the time of macro photography to the normal photography state, or when the zoom lens barrel is stored, the rear cam barrel 4 is further rotated in the reverse direction, and another rear side opposite to the stopper 25 is provided. The arm portion 10 of the front cam barrel 3 is brought into contact with the stopper 26 (see FIG. 10) (this is the stopper bump b
And). The stopper 26 is shaped so that the arm portion 10 comes into contact with the front cam barrel 3 during macro shooting while the front cam barrel 3 is moving forward in the optical axis direction, but does not come into contact with the stopper 26 during normal shooting. Then, by further applying reverse rotation from the macro shooting state, the storage state or the normal shooting state is set. At the same time, it is possible to rotate the image forward and take a normal image. The series of movements of the first group and the second group are as shown in FIG.

In this embodiment, the pins 16 and 18 are
By engaging the cam groups 19 and 20 with each other, when the front cam barrel 3 and the rear cam barrel 4 rotate, the lens group 8,
Although the configuration is such that 9 is moved in the optical axis direction, the lens groups 8 and 9 can also be moved in the optical axis direction by using a helicoid screw.

[0025]

As described above, according to the first aspect of the invention, it is possible to create an interval between the first group and the second group, which cannot be realized by the shape of the guide portion of the front cam barrel or the rear cam barrel. It is possible to set a specially required group interval. Accordingly, it is not necessary to particularly lengthen the guide portion for macro photography, and it is not necessary to increase the angle of the guide portion. Therefore, the rotation torque for driving the cam barrel can be reduced, and the rotation drive mechanism can be downsized. As a result, a compact zoom lens barrel can be obtained.

According to the second aspect of the present invention, since the front cam barrel and the rear cam barrel are in close contact with each other, the rotational force applied to the rear cam barrel can be accurately applied to the front cam barrel regardless of the rotation direction. Can be communicated.

According to the invention described in claim 3, the front cam barrel can be easily separated from the rear cam barrel.

According to the fourth aspect of the invention, the front cam barrel can be easily brought into close contact with the rear cam barrel.

According to the fifth aspect of the invention, the positional relationship between the front cam barrel and the rear cam barrel during forward rotation is that of a guide portion that continuously varies from a normal wide to tele. If the position is maintained and the positional relationship is shifted and then the image is rotated in the reverse direction, a certain arbitrary place can have a relationship between the first group and the second group that enables macro photography.

According to the sixth aspect of the present invention, it is possible to configure the positional relationship between the first group and the second group, which has a focal length other than the wide-angle for normal photography and a focal length other than tele at any position.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of a zoom lens barrel according to the present invention during normal shooting.

FIG. 2 is a sectional view of a main part of a zoom lens barrel according to the present invention during macro photography.

FIG. 3 is a diagram showing a positional relationship between a front cam barrel and a rear cam barrel during normal shooting of the zoom lens barrel according to the present invention.

FIG. 4 is a diagram showing a positional relationship between a front cam barrel and a rear cam barrel during macro photography of the zoom lens barrel according to the present invention.

FIG. 5 is a perspective view showing a positional relationship between a front cam barrel and a rear cam barrel during normal shooting of the zoom lens barrel according to the present invention.

FIG. 6 is a perspective view showing a positional relationship between a front cam barrel and a rear cam barrel during macro photography of the zoom lens barrel according to the present invention.

FIG. 7 is a perspective view of a fixed barrel.

FIG. 8 is a perspective view of a guide tube.

FIG. 9 is an enlarged view of a front cam guide groove formed in the rear cam barrel.

FIG. 10 is a view showing a stopper that restricts rotation of the front cam barrel.

FIG. 11 is a diagram showing the relationship between the rotation angle of the cam barrel and the positions of the first group and the second group.

[Explanation of symbols]

1 fixed tube 2 guide tubes 3 front cam cylinder 4 Rear cam barrel 8 1st group lens 9 2nd lens 10 arms 11 Front cam pin 12 spaces 13 Guide groove for front cam 13A slope 13B Vertical part 14 spring 15,17 Lens frame 16, 18 pin 19,20 Cam groove 21 guide groove 25,26 stopper

Claims (6)

[Claims] 1. A fixed barrel, a guide barrel supported by the fixed barrel and having a guide groove formed therein, a cam barrel rotatably provided in the guide barrel and having a guide portion formed therein, and in the cam barrel. There are provided two front and rear lens groups for zooming, a guided portion fixed to the lens frame of the zoom lens group and guided by the guide portion, and a biasing member for biasing the cam barrel in the optical axis direction. Biasing means, and by rotating the cam barrel around the optical axis, the guided portion moves along the guide groove, and moves in the optical axis direction without rotating the lens group for zooming. In the zoom lens barrel, the cam barrel is divided into two in the front and rear along the optical axis direction to form a front cam barrel and a rear cam barrel, and the guide portions are formed in each of the front cam barrel and the rear cam barrel. In addition, the front cam barrel has a front cam pin, and the rear cam barrel has a front cam pin. By providing guide grooves respectively and engaging the front cam pins with the front cam guide grooves, the front cam cylinder and the rear cam cylinder are connected to each other, while the front cam guide grooves are arranged in the optical axis direction. The front cam pin is guided by the tilted portion and moves in accordance with the rotation of the rear cam barrel, so that the positional relationship of the variable power lens group is changed by the guide portion. A zoom lens barrel characterized by being set at a position other than the relation. 2. The zoom lens barrel according to claim 1, wherein during normal shooting, the front cam barrel is brought into close contact with the rear cam barrel by the biasing means, and the front cam barrel is integrated with the rear cam barrel. The zoom lens barrel is characterized by the fact that it rotates. 3. The zoom lens barrel according to claim 1, wherein the guide barrel is provided with a stopper that restricts rotation of the front cam barrel, and the rear cam barrel is set to a predetermined amount or more during normal shooting. When rotated, the arm portion of the front cam cylinder having the front cam pin contacts the stopper to prevent the rotation of the front cam cylinder, and the front cam pin moves the inclined portion in one direction. A zoom lens barrel, wherein the front cam barrel is separated from the rear cam barrel. 4. The zoom lens barrel according to claim 3, wherein the guide barrel is provided with a stopper different from the stopper, the stopper being capable of contacting with the arm portion. When the rear cam barrel is rotated in the reverse direction in a state of being separated from the barrel, the arm portion contacts the other stopper to prevent the rotation of the front cam barrel, and the front cam pin moves the inclined portion in the opposite direction. By so doing, the front cam barrel is brought into close contact with the rear cam barrel. 5. The zoom lens barrel according to claim 1, wherein the guide portions of the front cam barrel and the rear cam barrel continuously change from wide to tele in normal use. The zoom lens group is formed into a shape that maintains the group relationship necessary for zooming, and by changing the positional relationship between the front cam barrel and the rear cam barrel during macro photography, the variable magnification lens group is capable of macro photography. A zoom lens barrel characterized by forming a relationship. 6. The zoom lens barrel according to claim 1, wherein the guide portions of the front cam barrel and the rear cam barrel continuously change from wide to tele in a normal use state. The zoom lens group is formed in a shape that maintains the group relationship required for zooming, and by changing the positional relationship between the front cam barrel and the rear cam barrel, the variable power lens group normally focuses from wide to other than telephoto. A zoom lens barrel having a distance lens configuration.