JPH0619487B2 - 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 Prior 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 a compact camera, the camera body and lens barrel are integrated, and the lens barrel is inside the camera body, so if the diameter of the lens barrel becomes large, the camera body will become large. The zoom mechanism of can not be applied as it is. In a compact camera, it is desirable not to increase the diameter of the lens barrel even when the zoom lens mechanism is provided.

[Object of the Invention] The present invention has been made based on the above viewpoint, and an object thereof is to provide a lens movement structure of a camera suitable for application to a zoom 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 circular cross section with a cam groove, which is immovable in the axial direction and is rotatably around the optical axis, is housed in the rear storage chamber of the movable barrel and is rotated by the movement of the movable barrel, and the inside of the cam barrel. And a guide for guiding the movement of the rear group lens, which is movably provided in the optical axis direction and which moves in the cam barrel by rotation of the cam barrel by engagement with the cam groove of the cam barrel. The rear group lens is formed into a substantially oval shape with a circular upper and lower parts missing, and the guide member is arranged in an arc-shaped space formed between the rear group lens and the cam barrel. The above object is achieved by the lens moving structure of the camera. With such a configuration, 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 in the moving amount of the rear lens group is equivalent to the moving 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, and further, the diameter of the cam barrel, that is, the diameter of the lens barrel can be increased without increasing the cam barrel. A guide member can be provided inside, and the zoom lens mechanism can be downsized.

[Embodiment of the Invention] FIG. 1 is an assembly perspective view showing an embodiment of the present invention, and shows an ultra-small zoom lens mechanism of a compact camera.

In the figure, 1 is a fixed cylinder, 2 is a movable cylinder, 3 is a cam cylinder, and 4
Is a front lens group unit, and 5 is a rear lens unit.

The moving barrel 2 includes a front housing chamber 6 for housing the front lens unit 4, a rear housing chamber 7 for housing the cam barrel 3, and guide bars 8a, 8b each having one end fixed to the moving barrel 2. I have it. The front lens group unit 4 includes the front lens group 9a,
9b and a holding member 10 for holding the front lens group 9a, 9b
By having the holding member 10 engage with the protrusions 11a and 11b formed in the front housing chamber 6, the holding member 10 is fixedly held in the front housing chamber 6 of the movable barrel 2. A shutter member 12 is arranged between the front lens groups 9a and 9b.

The rear group lens unit 5 is housed in the cam barrel 3 having a circular cross section. The rear group lens unit 5 is a movable rear group lens 1
3a, 13b, lens holders 14a, 14b for holding the rear group lenses 13a, 13b, and rear group lenses 13a, 1
Guide members 15a and 15b for guiding the movement of 3b,
It has a guide function for the rear group lenses 13a and 13b and a guide member 16 for preventing rotation of these lenses.
In the compact camera, the rear group lenses 13a and 13b have a larger diameter than the front group lenses 9a and 9b, and particularly the rear rear group lens 13b has a large diameter. Therefore, when the rear group lens 13b is formed by a normal circular lens, the rear group lens 1
It is necessary to increase the diameter of the cam barrel 3 that accommodates the guide members 15a, 15b and 16 and the guide members 15a, 15b and 16a, which leads to an increase in size of the camera body. In the present invention, the screen size is 24 × 36.
In consideration of the fact that the rear group lenses 13a and 13b have a size of mm, the rear group lenses 13a and 13b have a substantially oval shape in which the upper and lower portions of the circular shape are omitted in accordance with the screen size.
Also has a substantially oval shape. As a result, arcuate space portions are provided in the upper and lower portions between the cam barrel 3 and the lens holders 14a and 14b. The guide members 15a and 15b are arranged in the upper space portion, and the guide member 16 is arranged in the lower space portion. Therefore, it is not necessary to increase the diameter of the cam barrel 3. The rear lens groups 13a and 13b are respectively connected to the guide member 15 via the lens holders 14a and 14b.
It is slidably held by a, 15b and 16. One ends of the guide members 15a, 15b, 16 are coupled to the holding plate 17, and the other ends thereof are engaged with, for example, recesses (not shown) in the rear storage chamber 7 of the moving barrel 2. Lens holders 14a, 14
b is a pin 1 that engages with the cam grooves 18a and 18b of the cam barrel 3.
9a and 19b, and the lens holder 1
4a, 14b, that is, the rear lens groups 13a, 13b move along the guide members 15a, 15b, 16.

The cam barrel 3 is housed in the rear housing chamber 7 of the movable barrel 2 in a state where the rear lens group unit 5 is housed therein, and is easily held by a holding plate 17 connected to an open surface of the rear housing chamber 7. The cam barrel 3 has a pin 22 that engages with a cam groove 21 formed in a cam member 20 fixed to the lower surface of the fixed barrel 1. When the movable barrel 2 is associated with the fixed barrel 1, the pin 22 is provided. Is the moving cylinder 2
The cam groove 21 is engaged through an open portion of the lower surface (not shown), and by this engagement, the cam groove 21 is rotated by movement in the optical axis direction.

The movable barrel 2 accommodating the front lens group unit 4, the cam barrel 3 and the rear lens unit 5 has guide bars 8a and 8b inserted through guide holes (not shown) of the fixed barrel 1, and the through end of the guide bar is stopped. By fixing to the movable barrel 2 with 23a, 23b, the guide bars 8a, 8
It is held so as to be able to move forward and backward by sliding between b and the guide hole of the fixed barrel 1.

FIGS. 2 (A) and 2 (B) are explanatory views of the movement of the front lens group and the rear lens group having the configuration of FIG. 1, and FIG. 2 (A) shows a state in which the movable barrel is retracted, FIG. 6B shows a state in which the movable barrel is advanced. The operation of the configuration shown in FIG. 1 will be described below with reference to FIGS. 2 (A) and 2 (B).

The movable barrel 2 is moved forward to move the front lens groups 9a and 9b by L ₁ . The moving amount of the rear group lenses 13a and 13b required for the moving amount L _{1 of the} front group lenses 9a and 9b is L.
₂ , which is greater than L ₁ . Rear lens group 13a, 13b
Moves forward by L ₁ when the moving barrel 2 moves forward, and at the same time, moves forward by the difference ΔL between the moving amounts L ₁ and L _{2 due} to the rotation of the cam barrel 3. That is, the cam barrel 3 is rotated by the engagement between the cam groove 21 of the fixed barrel 1 and the pin 22 of the cam barrel 3 in accordance with the forward movement of the movable barrel 2, and by this rotation, the rear group lenses 13a, 1
3b is further advanced by .DELTA.L due to the engagement between the pins 19a, 19b and the cam grooves 18a, 18b. As a result, the desired amount of movement L _{2 is applied to} the rear group lenses 13a and 13b.
Is given.

In the embodiment described above, both the rear group lenses 13a and 13b are formed into a substantially oval shape. However, in a compact camera, the rear rear group lens 13b has a larger diameter, so only this rear group lens 13b has an oval shape. May be set. The oval lens can be easily formed by a plastic lens.

[Effects of the Invention] As described above, according to the present invention, the front lens group is housed and fixed in the front storage chamber of the movable barrel that is held in the fixed barrel so as to be able to move forward and backward, and the cam barrel is placed in the rear storage 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. Is configured to move in the optical axis direction inside the cam barrel, and further, the rear group lens is formed into a substantially oval shape, and a guide member is provided in an arc-shaped space formed between the rear barrel lens and the cam barrel. Therefore, 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 is given by the movement. Since only the shortage should be given by the cam barrel The length of the cam barrel can be shortened, and further, a guide member can be provided in the cam barrel without increasing the diameter of the cam barrel, that is, the diameter of the lens barrel. It is possible to provide a lens moving structure suitable for the camera.

[Brief description of drawings]

FIG. 1 is an assembly perspective view showing an embodiment of the present invention, and FIGS. 2 (A) and 2 (B) are explanatory views of movement of the front lens group and the rear lens group having the configuration of FIG. 3 ... Cam barrel, 13a, 13b ... Rear group lens, 14
a, 14b ... Lens holder, 15a, 15b, 16 ...
... Guide member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-49-74934 (JP, A) JP-A-63-43114 (JP, A) Practical application Sho-57-197007 (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. A front group lens that is housed and fixed in the front storage chamber of the movable barrel, and is housed in the rear storage chamber of the movable barrel that is axially immovable and rotatable about the optical axis, and is rotated by the movement of the movable barrel. A cam barrel having a circular cross section having a cam groove, and provided inside the cam barrel so as to be movable in the optical axis direction, and by engaging with the cam groove of the cam barrel, the inside of the cam barrel is rotated by the rotation of the cam barrel. A rear group lens that moves, and a guide member that guides the movement of the rear group lens, and the rear group lens has a substantially oval shape in which a circular upper portion and a lower portion are omitted. The guide member is arranged in an arc-shaped space formed between Lens movement structure of a camera to be.