U.S. patent application number 10/140871 was filed with the patent office on 2003-05-22 for adjustable lens assembly.
Invention is credited to Chang, Gan-Chieh, Chen, Chih-Wen, Chiang, Huang-Chen, Tu, Yin-fa.
Application Number | 20030095337 10/140871 |
Document ID | / |
Family ID | 21679754 |
Filed Date | 2003-05-22 |
United States Patent
Application |
20030095337 |
Kind Code |
A1 |
Tu, Yin-fa ; et al. |
May 22, 2003 |
ADJUSTABLE LENS ASSEMBLY
Abstract
An adjustable lens assembly includes a lens barrel for carrying
a lens, at least one guiding member having a shaft axis parallel to
the optical axis of the lens barrel for guiding the direction of
motion of the lens barrel, a gear shaft driven by a driving source,
a driving member meshing with the gear shaft, and a connection
mechanism connecting the lens barrel and the driving member. The
connection mechanism is capable of adjusting itself with multiple
degrees of freedom so that if there is three-dimensional skew bias
between the gear shaft and the optical axis or the guiding member,
the lens barrel can be driven smoothly.
Inventors: |
Tu, Yin-fa; (Taoyuan Hsien,
TW) ; Chiang, Huang-Chen; (Taoyuan Hsien, TW)
; Chen, Chih-Wen; (Hsinchu Hsien, TW) ; Chang,
Gan-Chieh; (Hsinchu Hsien, TW) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
21679754 |
Appl. No.: |
10/140871 |
Filed: |
May 9, 2002 |
Current U.S.
Class: |
359/696 ;
359/822 |
Current CPC
Class: |
G02B 7/023 20130101 |
Class at
Publication: |
359/696 ;
359/822 |
International
Class: |
G02B 015/14; G02B
007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 16, 2001 |
TW |
90128407 |
Claims
What is claimed is:
1. An adjustable lens assembly comprising: a lens barrel for
carrying lens; at least one guiding member having a shaft axis
parallel to the optical axis of said lens barrel for guiding moving
direction of said lens barrel; a gear shaft driven by a driving
source; a driving member meshing with said gear shaft; and a
connection mechanism connecting said lens barrel and said driving
member for providing multiple degree of freedom.
2. An adjustable lens assembly according to claim 1 wherein said
driving member is formed with a screw hole for meshing with said
gear shaft.
3. An adjustable lens assembly according to claim 1 wherein said
multiple degree of freedom including a linear movement and three
angular movements.
4. An adjustable lens assembly comprising at least: a lens barrel,
for carrying lens, formed with a pair of extrusions at the rim
thereof, and at least a convex portion formed on each inner wall of
said extrusion; at least one guiding member having a shaft axis
parallel to the optical axis of said lens barrel for guiding moving
direction of said lens barrel; a gear shaft driven by a driving
source; and a driving member, meshing with said gear shaft, having
a pair of slides engageable with said extrusions of said lens
barrel, and correspondent slot for engaging said convex
portion.
5. An adjustable lens assembly according to claim 4 wherein said
convex portion is a curvy member.
6. An adjustable lens assembly according to claim 4 wherein said
convex portion is a ball member.
7. An adjustable lens assembly according to claim 4 wherein said
convex portion is a resilient member.
8. An adjustable lens assembly according to claim 4 wherein said
driving member is formed with a screw hole for meshing with said
gear shaft.
9. An adjustable lens assembly comprising at least: a lens barrel,
for carrying lens, formed with a seat at the rim thereof, and a
hole formed on said seat; a connector, slidably mounted in said
hole, formed with a pair of extrusions keeping a distance
therebetween, and formed with at least a convex portion on each
inner wall of said extrusions; at least one guiding member having a
shaft axis parallel to the optical axis of said lens barrel for
guiding moving direction of said lens barrel; a gear shaft driven
by a driving source; and a driving member, meshing with said gear
shaft, having a pair of slides engageable with said extrusions of
said connector, and correspondent slot for engaging said convex
portion.
10. An adjustable lens assembly according to claim 9 wherein said
driving member is formed with a screw hole for meshing with said
gear shaft.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention generally relates to an adjustable lens
assembly applicable to a lens of a camera, camcorder, surveillance
system or the like, and more particularly relates to an adjustable
lens assembly in which a lead screw mechanism is used to move the
lens for the purpose of focusing or zooming.
[0003] 2. Related Art
[0004] In a lens module, in order to minimize the size, a lead
screw mechanism is usually used to move the lens for focusing or
zooming. When using the screw mechanism, the gear shaft and the
guiding elements should be well fabricated and mounted in parallel,
otherwise smooth movement cannot be obtained. Any unsuitable
tolerance in manufacturing or assembly of the gear shaft or the
guiding elements will cause bias in the elements. In order to solve
this problem, a prior method is to lessen the bias by improving the
precision of fabrication and assembly of the elements. Another
method is to increase the backlash between the gear shaft and the
meshed nut for absorbing the clearance or bias. Though the two
prior methods can solve the problem, the first one increases the
tooling cost of the elements and the time cost of assembly, while
the second one increases the backlash that will cause defects of
imprecision movement, vibration and noise.
[0005] In a transmission mechanism, two parallel axes C1 and C4
located in two parallel planes P1 and P2, as shown in FIG. 1, have
to be kept in parallel theoretically. However, due to tolerance in
manufacture and assembly, the distance between the two axes cannot
be kept constant along the direction of the axes; for example the
distances d1 and d2 do not remain the same between the axis C2 and
the axis C1. Technically, the difference, called the "bias,"
includes two conditions. One is inclination between two axes, for
example C1 and C2, located on a co-plane. The other is skew between
two axes, for example C1 and C3, located on two non-parallel
planes. Bias will cause the transmission mechanism to become
clogged, run awkwardly, noisily and waste power. Since the bias,
and especially the skew, occurs frequently in the fabrication and
assembly of a lens assembly, it is an important issue for the
industry that requires an effective solution.
[0006] Some prior arts for solving the aforesaid problem are
disclosed in U.S. Pat. Nos. 5,150,260 and 5,815,325. As shown in
FIG. 2, the prior art uses a rack and a screw for transmission. The
rack has an opening to allow inclination of the screw in the
parallel plane of the opening. However, when the axis of the screw
has a skew bias with the axis of the guide, an angular moment will
be generated when the screw drives the rack. The opening gives only
one dimension of freedom that is not enough for preventing the lens
assembly from being clogged or running awkwardly.
[0007] U.S. Pat. No. 5,150,260 provides an optical apparatus with a
moving member that has a gear portion meshing with a gear shaft
that is movable in the direction of the optical axis and is driven
by the rotation of the gear shaft to thereby move the lens holding
member in the direction of the optical axis. The moving member is
supported in a direction substantially orthogonal to the axial
direction of said gear shaft. U.S. Pat. No. 5,815,325 discloses a
lens assembly that comprises a lens barrel assembly for supporting
a lens barrel, one or more guide members for guiding the movement
of the lens barrel assembly in the direction of an optical axis, a
gear shaft that is rotated by a primary mover, and a drive linkage
for coupling the lens barrel assembly with the gear shaft. The
drive linkage has a drive nut portion meshing with the gear shaft
over a threaded partial circumference section thereof and movable
in the direction of the optical axis by the rotation of the gear.
The aforesaid two patents try to solve the skew bias by adjustments
of two degrees (a linear movement and a rotation), but the bias
doesn't include the skew of the axis in two different planes.
[0008] As described above, some conventional lead screw driving
mechanisms for lens assemblies provide only one direction of
adjustment, as illustrated in FIG. 2. Though some other mechanisms,
as disclosed in U.S. Pat. Nos. 5,150,260 and 5,815,325, further
provide means for adjusting rotational bias, the rotational
adjustment is still limited in a plane passing through the optical
axis. In other words, they do not solve the common problem of
three-dimensional bias of the driving shaft to the optical axis.
Another problem is the transmission method of the rack with an
opening that slips easily.
SUMMARY OF THE INVENTION
[0009] The object of the invention is therefore to provide an
adjustable lens assembly having a transmission mechanism with
multiple degrees of freedom that can solve the problem of skew bias
of the driving shaft to the optical axis.
[0010] To achieve the aforesaid object, an adjustable lens assembly
according to the invention includes a lens barrel for carrying the
lens, a guiding member having a shaft axis parallel to the optical
axis of the lens barrel for guiding the direction of movement of
the lens barrel, a gear shaft driven by a motor, a driving member
meshing with the gear shaft, and a connection mechanism connecting
the lens barrel and the driving member. The connection mechanism is
capable of adjusting itself with multiple degrees of freedom so
that if there is three-dimensional skew bias between the gear shaft
and the optical axis or the guiding member, the lens barrel can be
driven smoothly.
[0011] Further scope of applicability of the invention will become
apparent from the detailed description given hereinafter. However,
it should be understood that the detailed description and specific
examples, while indicating preferred embodiments of the invention,
are given by way of illustration only, since various changes and
modifications within the spirit and scope of the invention will
become apparent to those skilled in the art from this detailed
description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention will become more fully understood from the
detailed description given hereinbelow. However, this description
is for purposes of illustration only, and thus is not limitative of
the invention, wherein:
[0013] FIG. 1 is a descriptive drawing showing bias conditions of
inclination and skew;
[0014] FIG. 2 is an illustration showing a conventional lens
adjustment mechanism;
[0015] FIG. 3 is an illustrative sectional view of a first
embodiment of the invention;
[0016] FIG. 4 is a partial exploded view of the first embodiment of
the invention;
[0017] FIG. 5 is an illustrative sectional view of a second
embodiment of the invention; and
[0018] FIG. 6 is a partial exploded view of the second embodiment
of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The invention provides an adjustable lens assembly having a
transmission mechanism with multiple degrees of freedom that can
solve the problem of skew bias of the driving shaft to the optical
axis.
[0020] To achieve the aforesaid object, an adjustable lens assembly
according to the invention includes a lens barrel for carrying a
lens, a guiding member having a shaft axis parallel to the optical
axis of the lens barrel for guiding the direction of movement of
the lens barrel, a gear shaft driven by a driving source, a driving
member meshing with the gear shaft, and a connection mechanism
connecting the lens barrel and the driving member. The connection
mechanism is capable of adjusting itself with multiple degrees of
freedom so that if there is three-dimensional skew bias between the
gear shaft and the optical axis or the guiding member, the lens
barrel can be driven smoothly.
[0021] First Embodiment
[0022] As shown in FIGS. 3 and 4, the first embodiment of the
adjustable lens assembly according to the invention includes a lens
barrel 10, at least one guiding member 20, a gear shaft 30 and a
driving member 40. The driving member 40 meshes with the gear shaft
30 and is driven thereby so that the lens barrel 10 is movable
along the optical axis. The lens barrel 10 includes a lens 11. The
rim of the lens barrel 10 is formed with pairs of guiding slots 12
and guiding holes 12' for mounting on the guiding member 20 so that
the lens barrel 10 is movable along the axial direction of the
guiding member 20.
[0023] Each guiding member 20 is a rod laying in a direction
parallel to the axis of the lens barrel 10 so as to move the lens
barrel 10 in a path parallel to the optical axis. The gear shaft 30
is rotated by a motor 50. The driving member 40 is formed with a
screw hole 41 for engaging with the gear shaft 30, and a connection
mechanism, which will be described later, for connecting with the
lens barrel 10 in a self-adjustable manner.
[0024] By the aforesaid composition, the gear shaft 30 driven by
the motor 50 rotates to engage and move the driving member 40 along
the axial direction of the gear shaft 30. Through the connection of
the connection mechanism, the driving member 40 further moves the
lens barrel 10 along the axial direction of the guiding member 20.
The connection mechanism makes the driving member 40 adjustable
relative to the lens barrel 10 with multiple degrees of freedom so
that the lens barrel 10 can be smoothly driven along the optical
axis whenever there is skew bias generated between the axis of the
gear shaft 30 and the lens barrel 10.
[0025] In this embodiment, the connection mechanism between the
driving member 40 and the lens barrel 10 includes a pair of
extrusions 61 formed on the rim of the lens barrel 10, and a slide
62 formed on the driving member 40. The two extrusions 61 keep a
suitable distance from two inner walls that are each formed with a
convex portion 611. The convex portion 611 can be a resilient
curved member or a ball member connected on the extrusion 61. The
slide 62 couples with the extrusions 61 by engagement of a slot 621
formed on the slide 62 to the convex portions 611.
[0026] Please refer to the coordinate axis shown in the drawings.
The two extrusions 61 are formed with an opening facing the Y-axis
and two parallel walls in the Z-axis. The distance between the two
extrusions 61 in the X-axis is larger than width of the slide 62 in
the X-axis so that the driving member 40 can swing on the Y-axis
and on the Z-axis by the clearance. The driving member 40 can also
swing on the X-axis by the parallel walls on the Z-axis. By the
slot 621 formed in the X-axis and the Y-axis, which engages with
the convex portions 611, the driving member 40 can move along the
Y-axis. Therefore, the driving member 40 can move relative to the
lens barrel 10 with freedom of one linear movement and three
angular movements.
[0027] When the gear shaft 30 engages and moves the driving member
40 in the axial direction relative to gear shaft 30, the driving
member 40 moves the lens barrel 10 along the axial direction of the
guiding members 20. When there is a skew bias, caused by tolerance
of fabrication or assembly, between the axial direction of the gear
shaft 30 and the axial direction of the guiding members 20, the
connection mechanism between the driving member 40 and the lens
barrel 10 acts like a ball joint that allows the driving member 40
to rotate along the X, Y and Z axes and shift in the Y-axis so as
to absorb the bias and make the lens barrel 20 move smoothly.
[0028] Second Embodiment
[0029] FIGS. 5 and 6 show a second embodiment of a connection
mechanism applicable in an adjustable lens assembly of the
invention. The connection mechanism between the driving member 40
and the lens barrel 10 includes a seat 63 formed on rim of the lens
barrel 10, a slide 65 formed on the driving member 40, and a
connector 64. The seat 63 is formed with a hole 631 for receiving
the connector 64. A pair of extrusions 641 are formed on the
connector 64. The two extrusions 641 maintain a suitable distance
from two inner walls that are each formed with a convex portion
642. The slide 65 couples with the extrusions 641 by engagement of
the concave portions 651 formed on the slide 65 to the convex
portions 642.
[0030] Please refer to the coordinate axis shown in the drawings.
By the connector 64 that can be slid in the hole 631 along the
Y-axis, the height of the connector 64 and the lens barrel 10 can
be adjusted and rotated along the Y-axis. The two extrusions 641
form an opening facing the Y-axis and two parallel walls in the
Z-axis. The distance between the two extrusions 641 in the X-axis
is larger than the width of the slide 65 in the X-axis so that the
driving member 40 can swing on the Y-axis and on the Z-axis by the
clearance. The driving member 40 can also swing on the X-axis by
the parallel walls of the two extrusions 641 on the Z-axis.
Therefore, when the gear shaft 30 engages and moves the driving
member 40 in the axial direction relative to the gear shaft 30, the
driving member 40 moves the lens barrel 10 along the axial
direction of the guiding members 20. When there is a skew bias
between the axial direction of the gear shaft 30 and the axial
direction of the guiding members 20, the connection mechanism
between the driving member 40 and the lens barrel 10 acts like a
ball joint that allows the driving member 40 to rotate along the X,
Y and Z axes and shift in the Y-axis so as to absorb the bias and
make the lens barrel 20 move smoothly.
[0031] Please note that in the aforesaid embodiments, the convex
portion 611 and the slot 621, or the convex portion 642 and the
concave portions 651, can swap positions with each other and still
maintain their same functions.
[0032] As described above, the invention provides an adjustable
lens assembly having a transmission mechanism with multiple degrees
of freedom that can solve the problem of skew bias of the driving
shaft to the optical axis.
[0033] Through the invention being thus described, it will be
obvious that the same may be varied in many ways. Such variations
are not to be regarded as a departure from the spirit and scope of
the invention, and all such modifications as would be obvious to
one skilled in the art are intended to be included within the scope
of the following claims.
* * * * *