Photography – Having variable focal length of camera objective – Power zoom
Reexamination Certificate
2003-05-28
2004-03-09
Perkey, W. B. (Department: 2851)
Photography
Having variable focal length of camera objective
Power zoom
Reexamination Certificate
active
06704505
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority of Taiwan Patent Application Serial No. 091123920 filed on Oct. 17, 2003.
FIELD OF THE INVENTION
The present invention relates to an auto-zooming device, and more particularly, to an auto-zooming device used in a camera.
BACKGROUND OF THE INVENTION
Conventional zoom lenses used in a photographic apparatus usually work in two ways: manually or mechanically. The former, manual zooming, is obtained by rotating the lens with hands so that it can extend or withdraw. And the latter, auto-zooming, is generally obtained by using an additional driving apparatus, such as a motor, to move the lens.
FIG. 3
depicts a prior art of auto-zooming device. The auto-zooming device includes a lens
1
, an extension part
3
, a motor
5
and a screw
7
. The extension part
3
extends from the lens
1
and has a hole for engaging with the screw
7
(not shown in FIG.
3
). Accordingly, the screw
7
connects with the lens
1
through the extension part
3
. The motor
5
drives the screw
7
to rotate. When the screw
7
rotates, the lens
1
moves forward or backward with the screw
7
, which is indicated by arrows shown in FIG.
3
.
In general, the size of motor
5
limits the size of the whole lens
1
. However, with the trends that feature light-weighted and compact electronic devices, it is a very important task to develop lighter and more compact electronic devices.
SUMMARY OF THE INVENTION
One aspect of the present invention is to reduce the size and weight of the auto-zooming device in the camera.
The other aspect of the present invention is to lower down the noises generated when the lens is zooming in or out in the camera.
The present invention discloses an auto-zooming device used in a camera. The auto-zooming device includes a lens, a first positioning device, a second positioning device, a magnet and a coil. The first positioning device is disposed in the camera. The second positioning device is connected with the lens and engages with the first positioning device. When the second positioning device rotates, it moves axially along the first positioning device. Accordingly, the second positioning device drives the lens to move forward or backward to adjust the focal length. The magnet is connected with the second positioning device. The coil is disposed to loop around the magnet. When a current flows into the coil, the magnet is driven to rotate responsively by the magnetic force. The magnet can rotate selectively clockwise or counterclockwise according to the direction of the current, and also drive the second positioning device to rotate.
REFERENCES:
patent: 4828360 (1989-05-01), Maruyama
patent: 5678096 (1997-10-01), Wakabayashi et al.
Birch & Stewart Kolasch & Birch, LLP
Lite-On Technology Corporation
Perkey W. B.
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