JPH0843901A - Camera - Google Patents

Abstract

PURPOSE:To satisfy both demands for down sizing of a camera main body and increase of zoom ratio, regarding a camera which is provided with a settling trunk type lens- barrel so composed as to have a structure wherein an inner barrel which holds a front lens group and a rear lens group frame which holds a rear lens group set in rear of the front lens group are made movable back and forth in the optical axial direction by movement of an outer barrel. CONSTITUTION:A movable member 20 is attached integrally to an inner barrell 5 in the way the member 20 can be rotate freely and move back and forth in the inner barrel 15. The movable member 20 is provided with a cylindrical base part 20a which is extended in the inside of the inner barrel and behind a front lens group in the optical axis direction and a joining part 20b which is installed unitedly with the base part 20a and joined with a straightly proceeding groove 14d of an outer barrel 14 behind the inner barrel 15 in the way it can slide freely. A joining part 21b of a rear lens group frame 21 is joined with a cam groove 20c formed in the base part 20a of the movable member 20 in the way the joining part 21b can slide freely on the groove, and the joining part 21b is made possible to move on the base part 20a in the optical axis direction by rotary movement of the movable member 20, said movement is transmitted from the outer barrel 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a camera, and more particularly, a retractable lens barrel which is completely housed in the camera body when not in use and which is extended from the camera body when in use. It's about the camera.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional example of a camera having a lens barrel of this type. 4A and 4B are longitudinal sectional views showing an example of a conventional camera. FIG. 4A shows a state in which the lens barrel is housed, and FIG. 4B shows a state in which the lens barrel is completely extended (tele end state).
Are shown respectively.

The illustrated lens barrel 1 is a two-stage extension type zoom lens barrel, and includes a fixed barrel 3 fixed inside the camera body 2 and a fixed barrel 3 located inside the fixed barrel 3. An outer cylinder 4 protruding and retracting from the front end of the outer cylinder 4 in the optical axis direction, and an inner cylinder 5 located inside the outer cylinder 4 protruding and retracting from the front end of the outer cylinder 4 in the optical axis direction. The front lens group 6 is fixedly held. A helicoid (not shown) screwed with a helicoid (not shown) formed inside the fixed barrel 3 is engaged with the drive gear 7B via the moving gear 7A on the peripheral surface of the rear end of the outer barrel 5. The screw portion 4a is formed, and when the rotational force from the drive gear 7B is applied, the outer cylinder 5 becomes the fixed cylinder 3
On the other hand, while rotating, it moves back and forth in the optical axis direction.

A straight advance key 8 extending in the optical axis direction inside the outer cylinder 4 is attached to the outer cylinder 4 so as to move forward and backward integrally and rotatably, and a rear end portion 8a of the straight advance key 8 is provided. It engages with a straight groove 3a formed on the inner surface of the fixed barrel 3. A key groove 5a that engages with the straight advance key 8 is formed on the inner surface of the inner cylinder 5, and an engagement pin 5b that engages with a cam groove 4b formed on the inner surface of the outer cylinder 4 is formed on the outer surface. The cylinder 5 is the outer cylinder 4
It is designed to be moved back and forth in the direction of the optical axis without rotating due to the rotating motion of.

A rear lens group frame 10 holding a rear lens group 9 is located behind the front lens group 6. Rear lens group frame 10
Is formed with an engagement pin 10a that engages with a cam groove 4c formed on the inner surface of the outer cylinder 4, and the rear lens group frame 10 is separated from the front lens group 6 by the rotational movement of the outer cylinder 4. It can be moved back and forth in the direction of the optical axis while changing the.

[0006]

In such a retractable lens barrel, the zoom ratio can be increased as the maximum extension amount of the front lens group from the camera body is increased. Therefore, it becomes necessary to increase the length of each movable barrel, in the above example, the outer barrel 4 and the inner barrel 5 in the optical axis direction. If the length of each movable barrel becomes long, the thickness of the camera body, which must accommodate the elongated movable barrel, increases, and the camera becomes large accordingly. As a method of keeping the length of each moving cylinder short and increasing the amount of extension of the front lens group from the camera body,
Although it is conceivable to increase the number of stages of the movable barrel that is extended from the camera body, the larger the number of stages of the movable barrel, the larger the diameter of the lens barrel and the larger the body of the camera.

When the number of stages of the movable barrel is kept small, for example, when the movable barrel is composed of two stages of the outer barrel 4 and the inner barrel 5 as in the above-mentioned example, the number of feeding stages is not increased and the front lens group is not increased. In order to achieve both the increase in the amount of extension of 6 and the reduction in thickness of the camera body 2, the front lens group 6 is arranged in the inner cylinder 5 as close to the front side as possible, and the front lens group 6 is disposed outside the inner cylinder 5 in the tele end state. It is preferable that the length of the outer cylinder 4 and the inner cylinder 5 be shortened by increasing the amount of extension from the cylinder 4 as much as possible. In that case, if only the amount of the front lens group 6 extending from the camera body 2 is taken into consideration, the length of the outer cylinder 4 should be secured by the amount required for the amount of the inner cylinder 5 extending from the outer cylinder 4. It will be good.

However, since the rear lens group frame 10 is configured to move in the optical axis direction by being driven by the rotational movement of the outer cylinder 5, the outer cylinder 5 and the rear lens group frame 10 are always in the engaged state. In addition, the rear lens group 9 is moved closer to the front lens group 6 so that the telescopic system in which the amount of extension of the inner tube 5 from the outer tube 4 increases, and the amount of extension of the inner tube 5 into the outer tube 4 is increased. As the number of wide lenses increases, the front lens group 6 to the rear lens group 9
In practice, the length of the outer cylinder 4 depends on the amount of extension of the inner cylinder 5 from the outer cylinder 4 and the distance between the two lenses 6 and 9 in the wide end state. The difference from the distance between the two lenses 6 and 9 in the tele end state (strictly speaking, since the inner cylinder 5 slightly projects from the front end of the outer cylinder 4 in the wide end state, it becomes slightly shorter than that. But I had to make it longer.

FIG. 5 is a diagram schematically showing this point. FIG. 5A shows the stored state, FIG. 5B shows the wide end state, and FIG. 5C shows the tele end state. There is. Note that the reference numbers of each element are the same as those in FIG. In this example, as shown in (c) of FIG.
In order to ensure the engagement between the rear lens group frame 10 and the outer cylinder 4 approaching to, the overlapping portion of the outer cylinder 5 with the inner cylinder 4 is considerably long.

The present invention has been made in view of the above circumstances, and an object thereof is to adjust the distance between the front lens group held by the inner cylinder extended from the outer cylinder and the amount of extension of the inner cylinder in inverse proportion. In a camera including a lens barrel configured to move the rear lens group to be moved in the optical axis direction by movement of an outer cylinder, typically, rotational movement, an increase in zoom ratio and a reduction in size of the camera body can be achieved. It is to be able to achieve both.

[0011]

In order to solve the above-mentioned problems, a camera of the present invention has a base portion extending in the optical axis direction inside an inner cylinder forming a lens barrel and behind a front lens group, and a base portion of the base portion. A moving member having an engaging portion slidably engaged with an inner surface of the outer cylinder at a rear position of the inner cylinder at a rear end portion of the inner cylinder, and a moving member that moves in the optical axis direction with respect to the outer cylinder. A base portion of the moving member, which has a holding portion holding the rear lens group and an engaging portion slidably engaged with the base portion of the moving member, and which is transmitted from the outer cylinder via the engaging portion of the moving member. And a rear lens group frame which can be moved on the base in the optical axis direction by the movement of the.

Specifically, the outer cylinder is a rotary cylinder that moves in the optical axis direction while rotating in the circumferential direction around the optical axis,
It is characterized in that the above-mentioned moving member is engaged with the outer cylinder rotatably and integrally so as to move back and forth, and moves the rear lens group frame in the optical axis direction by the rotational movement transmitted from the outer cylinder.

More specifically, the inner cylinder is a straight advancing cylinder that is moved forward and backward in the optical axis direction without rotating due to the rotational movement of the outer cylinder, and the moving member is rotatable and forward and backward integrally with the inner cylinder. It is characterized by being provided in.

More specifically, a cam groove spirally extending in the optical axis direction is formed on the base of the moving member, and a straight groove extending parallel to the optical axis direction is formed on the inner surface of the inner cylinder. The engaging portion of the rear lens group frame is slidably engaged with the rectilinear groove via the cam groove.

The outer cylinder is a rotating cylinder of the first stage which is extended from the camera body.

[0016]

As described above, in the camera of the present invention, the rear lens group frame is not directly engaged with the outer cylinder,
The outer cylinder is engaged with the outer cylinder via a moving member that moves in the optical axis direction with respect to the outer cylinder, and the moving member has a base portion that extends in the optical axis direction inside the inner cylinder and behind the front lens group. The rear group lens frame has an engaging portion that engages with the outer cylinder at a rear position of the inner cylinder provided integrally with the base, and the rear lens group frame is moved along the optical axis on the base by the movement of the moving member transmitted from the outer cylinder. It is configured to move in the direction. Therefore, in the conventional camera, the relative positional relationship between the rear lens group and the rear lens group in the optical axis direction is always constant, whereas in the camera of the present invention, , The rear lens group frame moves on the base of the moving member to engage with the outer cylinder of the moving member (think of this as the engagement position of the rear lens group with the outer cylinder via the moving member). It is possible to change the relative positional relationship between the rear lens group and the rear lens group in the optical axis direction.

Thus, for example, by moving the rear lens group frame to the front end side on the base of the moving member in the tele end state, the rear group while the engaging position of the moving member with the outer cylinder is separated from the front lens group. The lens can be brought close to the front lens group, and when in the wide-angle end state, the rear lens group frame is moved to the rear end side on the base of the moving member, so that the engaging position of the moving member on the outer cylinder is adjusted to the front group. The rear lens group can be moved away from the front lens group while moving closer to the lens.

Therefore, according to the camera of the present invention, the front lens group is arranged considerably forward in the inner cylinder to increase the moving amount of the front lens group from the camera body and to increase the number of moving stages without increasing the inner lens barrel. Moreover, since the length of the outer cylinder can be shortened, it is possible to achieve both an increase in zoom ratio and a reduction in size of the camera body.

[0019]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a vertical sectional view of a camera according to an embodiment of the present invention. FIG. 1 (a) shows a housed state of a lens barrel, and FIG. 1 (b) shows a telephoto end state of the lens barrel. ing. FIG. 2 is an exploded perspective view of the lens barrel shown in FIG.

The lens barrel 11 of the illustrated camera is a two-stage extension type zoom lens barrel, and includes a fixed barrel 13 fixed inside the camera body 12 and a fixed barrel located inside this fixed barrel 13. An outer cylinder 14 protruding and retracting in the optical axis direction from the front end of the cylinder 13,
An inner cylinder 15 that is located inside the outer cylinder 14 and projects in and out from the front end of the outer cylinder 14 in the optical axis direction is provided. Inside the inner cylinder 15, a front lens group 16 is fixedly held.

At the rear end of the outer cylinder 14, a key member 17 having a straight-moving key 17a extending inside the outer cylinder 14 in the optical axis direction is provided.
It is attached to 14 and can be moved forward and backward and freely rotatable. The key member 17 has a gear 19 that engages with a drive gear 18 rotatably attached to the fixed barrel 13 and extending in the optical axis direction.
Is rotatably attached.

Inside the fixed cylinder 13, a helicoid 13 screwed with a helicoid 14a formed on the outer peripheral surface of the rear end portion of the outer cylinder 14 is screwed.
a and a protrusion 17b protruding from the outer peripheral surface of the rear end of the key member 17
A straight groove 13b slidably engaged therewith is formed.
A gear portion 14b that engages with the gear 19 is also formed on the outer peripheral surface of the rear end portion of the outer cylinder 14, and the drive gear 18 is interposed via the gear 19.
When the rotational force from the external cylinder 14 is applied to the screw portion 14b of the external cylinder 14,
The key member 17 moves in the optical axis direction while rotating with respect to the fixed barrel 13, and the key member 17 moves in the optical axis direction together with the outer barrel 14 without rotating with respect to the fixed barrel 13.

On the outer peripheral surface of the rear end portion of the inner cylinder 15, a pin 15a slidably engaged with a cam groove 14c formed on the inner surface of the outer cylinder 14.
Is formed, and the straight key of the key member 17 is formed on the inner surface of the inner cylinder 15.
A key groove 15b extending in parallel with the optical axis direction is formed so as to slidably engage with 17a. The inner cylinder 15 is driven by the rotational movement of the outer cylinder 14, and moves in the optical axis direction with respect to the outer cylinder 14 without rotating. Further, a moving member 20 is attached to the rear end of the inner cylinder 15 so as to be rotatable with respect to the inner cylinder 15 and move forward and backward.

The moving member 20 has a cylindrical base portion 20a extending inside the inner cylinder 15 and behind the front lens group 16 in the optical axis direction.
And an engaging portion 20b integrally provided with the base portion 20a at the rear end of the base portion 20a. The engaging portion 20b slides on a straight groove 14d formed in the inner surface of the outer cylinder 14d and extending in the optical axis direction. It is movably engaged. The moving member 20 rotates integrally with the outer cylinder 14, and is pulled by the inner cylinder 15 driven by the rotary motion of the outer cylinder 14 and, together with the inner cylinder 15, moves in the optical axis direction with respect to the outer cylinder 14. It is designed to move.

A rear lens group frame 21 is arranged inside the moving member 20. The rear group lens frame 21 is composed of an annular holding portion 21a holding the rear group lens 21 and a pin-shaped engaging portion 21b protruding from the outer peripheral surface of the holding portion 21a.
Is slidably engaged with a cam groove 20c formed in the base portion 20a of the moving member 20 and a straight groove 15c formed in the inner surface of the inner cylinder 15 and extending in the optical axis direction through the cam groove 20c. Have been combined. The rear lens group frame 21 is driven by the rotational movement of the moving member 20 transmitted from the outer cylinder 14, and moves on and off the base 20a of the moving member 20 in the optical axis direction without rotating.

The straight-moving groove 20d formed on the outer peripheral surface of the base portion 20a of the moving member 20 and extending in the optical axis direction is a groove for assembling which is used when the moving member 20 is attached to the inner cylinder 15. It has nothing to do with the movement of the member 20.

Next, the lens barrel constructed as described above
The action of 11 will be described. 3A and 3B are diagrams schematically showing the operation of the lens barrel 11, where FIG. 3A shows the stored state, FIG. 3B shows the wide end state, and FIG. 3C shows the tele end state. ing.

When in the stored state as shown in FIG.
The outer cylinder 14 and the inner cylinder 15 are completely housed in the fixed cylinder 13, and at this time, the rear lens group frame 21 includes the base 20a of the moving member 20.
It is located near the rear end of. When a rotational force is applied to the outer cylinder 14 from the drive gear 18 described above, the outer cylinder 14 advances in the optical axis direction while rotating. Due to this rotational movement of the outer cylinder 14, the inner cylinder 15
Is advanced from the front end of the outer cylinder 14 and is pulled by the outer cylinder 14 so that the moving member 20 rotates integrally with the outer cylinder 14 and advances in the optical axis direction with respect to the outer cylinder 14. At this time, the rear group lens frame 21 is advanced in the optical axis direction on the base 20a of the moving member 20 by the rotational movement of the moving member 20 transmitted from the outer cylinder 14, and the rear group lens 22 and the front group lens 16 are separated from each other. The distance between is adjusted.

As shown in FIGS. 2B and 2C, the rear lens group 22 which is separated from the front lens group 16 in the wide end state is separated from the front lens group 16 by the rear lens group frame 21 in the tele end state.
Moves toward the front end of the base portion 20a of the moving member 20 and approaches the front lens group 16.

As is clear from comparison with the above-mentioned conventional example (FIGS. 4 and 5), the lens barrel of the present embodiment.
In 11, the rear lens group frame 21 is engaged with the outer cylinder 14 via the moving member 20 and is movable in the optical axis direction on the base 21a of the moving member 20 extending in the inner cylinder 15 in the optical axis direction. Since it has been
The length of the outer cylinder 14 can be shortened without changing the amount of the front lens group 16 extending from the camera body 12 in the telephoto end state, which enables the camera body 12 to be made thin. ing.

Although the embodiment of the camera of the present invention has been described above, the camera of the present invention is not limited to the specific mode of the embodiment, and various modifications can be made.

For example, in the above-mentioned embodiment, the moving member 20 is constructed so as to move forward and backward together with the inner cylinder 15 in the optical axis direction. Good.

The present invention can be applied not only to a camera having a two-stage extension type lens barrel but also to a camera having a three-stage extension type lens barrel having a larger number of movable barrels. Is.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a camera according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of the lens barrel shown in FIG.

FIG. 3 is a diagram showing the operation of the lens barrel shown in FIG.

FIG. 4 is a vertical sectional view showing an example of a conventional camera.

FIG. 5 is a diagram showing an operation of a lens barrel of a conventional camera.

[Explanation of symbols]

 11 Lens barrel 12 Camera body 13 Fixed barrel 13a Helicoid 13b Straight groove 14 Outer barrel 14a Helicoid 14b Screw part 14c Cam groove 14d Straight groove 15 Inner barrel 15a Pin 15b Key groove 15c Straight groove 16 Front lens 17 Key member 17a Straight key 18 Drive gear 20 Moving member 20a Base 20b Engaging part 20c Cam groove 21 Rear lens group frame 21a Holding part 21b Engaging part 22 Rear group lens

Claims (5)

[Claims] 1. An outer cylinder protruding and retracting in the optical axis direction from a camera body, an inner cylinder located inside the outer cylinder and protruding and retracting in the optical axis direction from a front end of the outer cylinder, and retained inside the inner cylinder. A lens barrel having a rear group lens located behind the front group lens and a rear group lens located behind the front group lens, wherein an optical axis direction is provided inside the inner cylinder and behind the front group lens. A base portion extending to the rear portion, and an engagement portion integrally provided with the base portion at a rear end portion of the base portion and slidably engaged with an inner surface of the outer cylinder at a rear position of the inner cylinder, A moving member that moves in the optical axis direction with respect to the outer cylinder; a holding portion that holds the rear group lens; and an engaging portion that slidably engages with a base portion of the moving member. After being moved in the optical axis direction on the base by the movement of the base of the moving member transmitted from the outer cylinder via the engaging portion Camera, characterized in that the lens frame, is provided. 2. The outer cylinder is a rotary cylinder that advances and retreats in the optical axis direction while rotating in the circumferential direction around the optical axis, and the movable member is engaged with the outer cylinder so as to be rotatable integrally and forward and backward. 2. The rear lens group frame is moved in the optical axis direction by the rotational movement transmitted from the cylinder.
The listed camera. 3. The inner cylinder is a rectilinear cylinder that is moved forward and backward in the optical axis direction without rotating by the rotational movement of the outer cylinder, and the moving member is provided rotatably and integrally with the inner cylinder. The camera according to claim 2, wherein the camera is provided. 4. A cam groove spirally extending in the optical axis direction is formed on the base of the moving member, and a straight groove extending parallel to the optical axis direction is formed on the inner surface of the inner cylinder. 4. The camera according to claim 3, wherein the engaging portion of the group lens frame is slidably engaged with the rectilinear groove via the cam groove. 5. The camera according to claim 2, wherein the outer cylinder is a first-stage rotating cylinder that is extended from the camera body.