JPH0619486B2 - Camera lens moving structure - Google Patents

Description

The present invention relates to a lens moving structure of a camera, and can be used for an ultra-small zoom lens mechanism of a compact camera and the like.

[Description of the Related Art] When a zoom lens mechanism is provided in a compact camera, unlike a single lens reflex camera in which the lens barrel is detachable from the camera body, in the compact camera, the camera body and the lens barrel are integrated. Since the length of the body is limited, the zoom lens mechanism of a single lens reflex camera cannot be applied as it is. That is, in a compact camera, it is desirable that the lens barrel be as short as possible.

[Object of the Invention] The present invention has been made based on the above viewpoint, and an object of the present invention is to provide a lens movement structure of a camera suitable as an ultra-small zoom lens mechanism of a compact camera.

[Means for Achieving the Purpose] In the present invention, a fixed cylinder, a front storage chamber that is held by the fixed cylinder so as to be able to move forward and backward, and has a front storage chamber on the side exposed from the fixed cylinder, and a rear portion on the opposite side A movable barrel having a storage chamber, a front group lens housed and fixed in a front storage chamber of the movable barrel,
A cam barrel having a cam groove, which is rotatably fixed in the axial direction and is housed in the rear storage chamber of the movable barrel and which rotates by the movement of the movable barrel, and a movable inside of the cam barrel in the optical axis direction. A rear lens group which is provided and moves in the cam cylinder by rotation of the cam cylinder by engagement with the cam groove of the cam cylinder, and when the front lens group is moved by the movement of the movable cylinder. The above object is achieved by a lens moving structure of a camera which gives the rear lens group a moving amount of the front lens group and a moving amount of the cam barrel due to rotation.

According to this structure, since the cam barrel is housed inside the moving barrel, the length of the cam barrel is canceled by the moving barrel, and the moving amount of the front lens group out of the moving amount of the rear lens group. Since a considerable amount is given by the movement and only the shortage is given by the cam barrel, the length of the cam barrel can be shortened and the zoom lens mechanism can be downsized.

[Embodiment of the Invention] FIGS. 1 (A) and 1 (B) are explanatory views of the principle of the present invention. FIG. 1 (A) shows a standard photographing operation, and FIG. 1 (B) shows a telephoto photographing operation. Shows.

In these figures, 1 is a fixed barrel, 2 is a movable barrel, and 3 is a cam barrel as a rear lens group moving member. The moving tube 2 is
It can move forward and backward with respect to the fixed barrel 1, and holds the front lens group 4 in a fixed manner. The cam barrel 3 is housed inside the movable barrel 2 and houses the rear lens group 5. The cam barrel 3 is moved along with the movable barrel 2 while being carried by the movable barrel 2, and in response to this movement, rotates about an axis aa ′. The rear lens group 5 is rotated by the cam barrel 3 to cause the cam barrel 3 to move.
The inside is moved in the direction of the axis aa '. The rear lens group 5 approaches the front lens group 4 as the movable barrel 2 moves forward,
The backward movement causes the cam barrel 3 to rotate so as to move away from the front lens group 4. Movement amount ΔL of the rear lens group 5 by the rotation of the cam barrel 3, the difference between the moving distance L ₁ of the front lens group 4 and the movement amount L ₂ of the rear lens group 5 (L 1 _{-L 2)} and so as Is set to.

With such a structure, the moving barrel 2 is moved by the moving amount L of the front lens group 4.
_When it is moved forward by ₁ , the rear lens group 5 is moved forward by L ₁ by the movement of the movable barrel 2 and is moved forward by ΔL by the rotation of the cam barrel 3. Since the movement amount ΔL is the difference between the moving distance L ₂ of the rear lens group 5 and the moving amount L ₁ of the front lens group 4, the rear lens group 5
Will move forward by L ₂ . Therefore, the length of the cam barrel 3 that gives the amount of movement of ΔL to the rear lens group 5 is sufficient, and it is not necessary to make the length that gives the original amount of movement L _2, and the length of the cam barrel 3 and the rear lens group 5 are not required. The length of the guide member (not shown) can be shortened.

FIG. 2 is an assembly perspective view showing an embodiment of the present invention, and shows a zoom lens mechanism of a compact camera.

In the figure, 10 is a fixed barrel, 11 is a movable barrel, 12 is a cam barrel as a rear lens group moving member, 13 is a front lens group unit, and 14 is a rear lens group unit.

The movable barrel 11 includes a front storage chamber 15 for storing the front lens group unit 13 and a rear storage chamber 16 for storing the cam barrel 12.
And a guide bar 1 whose one end is fixed to the moving barrel 11.
7a and 17b. Front group lens unit 13
Is the front lens group 18a, 18b and the front lens group 18a,
And a holding member 19 for holding 18b.
Is engaged with the projections 19a and 19b formed in the front storage chamber 15 to be fixedly held in the front storage chamber 15 of the movable barrel 11. Reference numeral 20 denotes a shutter member, which is the front lens group 18
It is arranged between a and 18b.

The rear lens group unit 14 is housed in the cam barrel 12. The rear lens group unit 14 includes rear lens groups 21a and 21b.
And lens holders 22a and 22b for holding the rear group lenses 21a and 21b, guide bars 23a and 23b of the rear group lenses 21a and 21b, and a guide bar 24 for preventing rotation of the rear group lenses 21a and 21b. ing. The rear group lenses 21a and 21b are respectively provided with lens holders 22a and 22b.
It is slidably held by the guide bars 23a, 23b and 24 via. One ends of the guide bars 23a, 23b, 24 are connected to the holding plate 25, and the other ends thereof are movable cylinders 11.
For example, it engages with a recess (not shown) in the rear storage chamber 16. The lens holders 22a and 22b have pins 27a and 27b that engage with the cam grooves 26a and 26b of the cam barrel 12,
The rotation of the cam barrel 12 causes the lens holders 22a and 22b, that is, the rear lens groups 21a and 21b to move to the guide bars 23a and 23.
It is designed to move along b and 24. Cam barrel 1
The amount of movement ΔL of the rear group lenses 21a and 21b due to the rotation of 2
Is as described in the explanation of the principle.

The cam barrel 12 is housed in the rear housing chamber 16 of the moving barrel 11 in a state where the rear lens group unit 14 is housed therein, and is easily rotated.
It is held by a holding plate 25 connected to the open surface of the rear storage chamber 16. The cam barrel 12 has a pin 3 that engages with a cam groove 29 formed in a cam member 28 fixed to the lower surface of the fixed barrel 10.
0, and when the moving barrel 11 is associated with the fixed barrel 10,
The pin 30 is adapted to engage with the cam groove 29 through an open portion of the lower surface of the movable barrel 11 which is not shown.

The movable barrel 11 in which the front lens unit 13, the cam barrel 12, and the rear lens unit 14 are housed has guide bars 17a and 17b inserted through guide holes (not shown) of the fixed barrel 10, and a penetrating end of the guide bar is stopped. By being fixed to the moving barrel 11 by 31a and 31b, it is held so as to be able to move forward and backward with respect to the fixed barrel 10.

In the abovementioned constituent elements above, the front lens group 18a by the advancement of the movable cylinder 11, when the 18b of the _{L 1} is moved, the rear lens group 21a in this movement, and at the same time 21b is _{L 1} moves, the cam groove 29 of the fixed barrel 10 cams The cam barrel 12 is rotated by the engagement of the barrel 12 with the pin 30, and this rotation causes the rear lens group 21
a, 21b are pins 27a, 27b and cam grooves 26a, 26
The engagement with b further advances by ΔL. As a result, as described in the explanation of the principle, the rear lens group 2
The desired movement amount L ₂ is given to 1a and 21b.

In the embodiment described above, the oval-shaped rear group lens in which the upper portion and the lower portion are omitted is used in consideration of the shape of the photographing screen. As a result, the upper and lower spaces between the rear lens group and the cam barrel 12 are utilized to guide the guide bars 23a, 2a.
3b and 24 can be provided, there is no need to increase the diameter of the cam barrel 12, and there is an advantage that the enlargement of the camera body can be prevented.

[Effects of the Invention] As described above, according to the present invention, the front lens group is housed and fixed in the front housing chamber of the movable barrel held in the fixed barrel so as to be able to move forward and backward, and the cam barrel is housed in the rear housing chamber. It is immovably and rotatably housed in the axial direction. When the movable barrel moves, the front lens group and the cam barrel move together, and the cam barrel rotates. This rotation causes the rear lens group in the cam barrel to move. Since it is configured to move in the optical axis direction inside the cam barrel, the length of the cam barrel is canceled by the moving barrel because the cam barrel is housed inside the moving barrel. The amount corresponding to the movement amount of the front lens group is given by the movement, and only the shortage is given by the cam barrel, so that the length of the cam barrel can be shortened. The projection length of the lens barrel from the camera Therefore, it is possible to provide a lens movement structure of a camera suitable as an ultra-small zoom lens mechanism of a compact camera.

[Brief description of drawings]

1 (A) and 1 (B) are explanatory views of the principle of the present invention, and FIG. 2 is a configuration diagram showing an embodiment of the present invention. 1, 10 ... Fixed cylinder, 2, 11 ... Moving cylinder, 3, 12 ...
... Cam tube, 4, 18a, 18b ... Front group lens, 5, 2
1a, 21b ... Rear group lens

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-60-218636 (JP, A) Actually open 61-188112 (JP, U) Actually open 47-27936 (JP, U)

Claims (1)

[Claims] 1. A fixed barrel, a movable barrel which is held by the fixed barrel so as to be able to move forward and backward, has a front storage chamber on the side exposed from the fixed barrel, and a rear storage chamber on the opposite side. It has a front lens group which is housed and fixed in the front housing chamber of the movable barrel, and a cam groove which is axially immovably and rotatably housed in the rear housing chamber of the movable barrel and which is rotated by the movement of the movable barrel. A cam barrel; and a rear lens group that is provided inside the cam barrel so as to be movable in the optical axis direction and that moves in the cam barrel by rotation of the cam barrel by engagement with a cam groove of the cam barrel. Then, when the front lens group is moved by the movement of the movable barrel,
A lens moving structure for a camera, wherein the moving amount of the front lens group and the moving amount of the cam barrel are given to the rear lens group.