U.S. patent application number 15/401177 was filed with the patent office on 2017-12-14 for apparatus for auto focus.
This patent application is currently assigned to JAHWA electronics Co., Ltd.. The applicant listed for this patent is JAHWA electronics Co., Ltd.. Invention is credited to Hee Seung KIM, In Soo KIM, Masahiro TAKASHIMA.
Application Number | 20170357077 15/401177 |
Document ID | / |
Family ID | 60572608 |
Filed Date | 2017-12-14 |
United States Patent
Application |
20170357077 |
Kind Code |
A1 |
KIM; Hee Seung ; et
al. |
December 14, 2017 |
APPARATUS FOR AUTO FOCUS
Abstract
Disclosed is an apparatus for auto focus, which includes a first
frame having a magnet, a second frame having an auto focus (AF)
coil for moving the first frame in an optical axis direction and a
yoke giving an attractive force to the magnet, and a plurality of
balls arranged in the optical axis direction and located between
the first frame and the second frame so that the first frame and
the second frame are maintained to be spaced apart from each other.
An entire height of the plurality of balls is equal to or higher
than a height of the magnet on the basis of the optical axis
direction.
Inventors: |
KIM; Hee Seung; (Seoul,
KR) ; KIM; In Soo; (Gyeonggi-do, KR) ;
TAKASHIMA; Masahiro; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
JAHWA electronics Co., Ltd. |
Chungcheongbuk-do |
|
KR |
|
|
Assignee: |
JAHWA electronics Co., Ltd.
Chungcheongbuk-do
KR
|
Family ID: |
60572608 |
Appl. No.: |
15/401177 |
Filed: |
January 9, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02K 33/16 20130101;
H02K 7/08 20130101; H02K 11/33 20160101; G02B 7/08 20130101; G02B
27/646 20130101; H02K 11/215 20160101; G02B 7/09 20130101; H02K
1/12 20130101; H02K 1/34 20130101 |
International
Class: |
G02B 7/09 20060101
G02B007/09; G02B 27/64 20060101 G02B027/64; H02K 33/16 20060101
H02K033/16; H02K 11/215 20060101 H02K011/215; H02K 1/12 20060101
H02K001/12; H02K 1/34 20060101 H02K001/34; H02K 11/33 20060101
H02K011/33 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 9, 2016 |
KR |
10-2016-0071581 |
Claims
1. An apparatus for auto focus, comprising: a first frame having a
magnet; a second frame having an auto focus (AF) coil for moving
the first frame in an optical axis direction and a yoke being
provided at a back of the auto focus coil and giving an attractive
force to the magnet; and a plurality of balls arranged in the
optical axis direction and located between the first frame and the
second frame so that the first frame and the second frame are
maintained to be spaced apart from each other, wherein an entire
height of the plurality of balls is equal to or higher than a
height of the magnet on the basis of the optical axis direction and
an entire height of the yoke is equal to or higher than the entire
height of the plurality of balls, and a side of the first frame
where the magnet is provided and a side of the second frame where
the auto focus coil is provided face each other, and the plurality
of balls are positioned between the side of the first frame where
the magnet is provided and the side of the second frame where the
AF coil and the yoke are provided.
2. The apparatus for auto focus according to claim 1, wherein the
plurality of balls includes: a first ball group having an n (n is a
natural number of 3 or above) number of balls arranged together
along the optical axis direction; and a second ball group having an
m (m is a natural number of 3 or above) number of balls provided at
a location different from the first ball group and arranged
together along the optical axis direction, wherein a height of all
balls included in the first ball group or the second ball group is
equal to or higher than the height of the magnet on the basis of
the optical axis direction.
3. The apparatus for auto focus according to claim 2, wherein an
uppermost ball which is a ball located at an uppermost location in
the first ball group or the second ball group is provided at a
height equal to or higher than a top end of the magnet on the basis
of the optical axis direction.
4. The apparatus for auto focus according to claim 3, wherein the
uppermost ball has a center point at a height equal to or higher
than the top end of the magnet on the basis of the optical axis
direction.
5. The apparatus for auto focus according to claim 4, wherein an
outer circumference of a top end of the uppermost ball is located
at a height equal to or higher than the top end of the magnet,
which is moved to an uppermost location by means of auto focusing,
on the basis of the optical axis direction.
6. The apparatus for auto focus according to claim 2, wherein a
lowermost ball which is a ball located at a lowermost position in
the first ball group or the second ball group is provided at a
height equal to or lower than a bottom end of the magnet on the
basis of the optical axis direction.
7. The apparatus for auto focus according to claim 6, wherein the
lowermost ball has a center point at a height equal to or lower
than the bottom end of the magnet on the basis of the optical axis
direction.
8. The apparatus for auto focus according to claim 7, wherein an
outer circumference of a bottom end of the lowermost ball is
located at a height equal to or lower than the bottom end of the
magnet, which is moved to a lowermost location by means of auto
focusing, on the basis of the optical axis direction.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to an apparatus for auto
focus, and more particularly, to an apparatus for auto focus having
improved tilt performance by using structures and arrangements of a
ball and an auto focus (AF) magnet.
BACKGROUND ART
[0002] As the hardware technique for image processing is being
developed and also the user needs on image photographing is
increasing, an auto focus (AF) function and an optical image
stabilization (OIS) function are implemented not only at an
independent camera but also at a camera module mounted to a mobile
terminal such as a cellular phone and a smart phone.
[0003] The auto focus function is to adjust a focus distance to a
subject by linearly using a lens or a lens assembly in an optical
axis direction so that a clear image is generated at an image
sensor (CMOS, CCD or the like) provided at a rear end of the
lens.
[0004] In order to implement the auto focus function, various
methods may be used. Representatively, a magnet (a permanent
magnet) is installed at an AF carrier (or, a mover), a coil is
installed at a stator (or, a housing, or another type of carrier),
and a power of a suitable level is applied to the coil to generate
an electromagnetic force to the coil (provided at the stator) and
the magnet (provided at the mover) to move the mover in an optical
axis direction.
[0005] In addition, recently, a device, or an actuator, in which
the AF and OIS functions are integrated is used. In this case, a
structure for moving an OIS carrier (or, a frame, a lens assembly
or the like) having a lens loaded thereon in the AF carrier in an
X-axis and/or Y-axis direction perpendicular to the optical axis is
integrally implemented together with the AF structure described
above. In some cases, a lens may be loaded on the AF carrier, and
an OIS carrier provided out of the AF carrier may be provided to
move in a direction perpendicular to the optical axis
direction.
[0006] Meanwhile, in an existing device in which only the AF
function is provided or the AF and OIS functions are provided
together, balls 510-1, 510-2 arranged in the same direction as the
optical axis are interposed between an AF carrier 500 (the mover)
and a housing 400 (the stator, FIG. 2) in order to improve the
behavior characteristics of the AF carrier 500 moving in the
optical axis direction, as shown in FIGS. 1 and 2.
[0007] In this structure, a suitable distance may be continuously
maintained between the mover and the stator, and a frictional force
is minimized by means of rotation of the balls and point contacts
with the balls, so that the AF carrier may move more smoothly and
accurately in the optical axis direction.
[0008] In this case, a yoke 420 (FIG. 2) is mounted to the housing
400 (the stator, FIG. 2) to generate an attractive force to a
magnet 520 provided at the AF carrier 500 so that the point contact
between the AF carrier 500 and the ball 510 may be effectively
maintained.
[0009] However, in the existing technique, in order to enhance the
attractive force between the magnet 520 and the yoke, as shown in
FIG. 1 and FIG. 2(a), the magnet 520 generating an attractive force
with the yoke is designed as large as possible so that its height
D2 is equal to or higher than an entire height D1 of the balls 510
which physically support the AF carrier 500 and the housing.
[0010] In this configuration, as shown in FIG. 2(b), if the AF
carrier 500 moves downwards based on the optical axis direction by
means of AF operation, the magnet 520 loaded on the AF carrier 500
also moves downwards, and thus an attractive force is relatively
strongly applied between the magnet 520 and the yoke 420 in a
region where the balls do not support, thereby generating a tilt
fault .theta.1 in a horizontal direction.
[0011] In another point of view, FIG. 2(c) shows that the AF
carrier 500 moves upwards on the basis of the optical axis
direction by means of AF operation. In this case, a region where
the balls do not support is generated above the magnet 520, and in
this region, a detachment may be generated by a predetermined angle
.theta.2 in a lower direction due to the attractive force between
the yoke 420 and the magnet 520, thereby causing a tilt fault.
[0012] Therefore, in the existing technique, if the AF carrier 500
moves in the optical axis direction, an attractive force is applied
between the magnet 520 and the yoke 420 in a region where the balls
510 do not physically support, which may break the balance of the
AF carrier 500 and thus resultantly cause tilt faults .theta.1 and
.theta.2 of the AF carrier 500 as shown in FIG. 2(d).
[0013] The tilt faults deform a light path passing to an image
sensor 600 through the lens as much as a maximum separation angle
(.theta.=.theta.1+.theta.2), thereby causing an error in focusing
as much, and thus a problem is caused in generating a clear
image.
[0014] Recently, a camera module loaded on a smart phone or the
like is implemented with a lightweight and slim design. If the
camera module has such a slim design, a ratio of width to thickness
of the AF carrier increases further, and thus the tilt problem of
the AF carrier may become more serious.
DISCLOSURE
Technical Problem
[0015] The present disclosure is designed to solve the problems of
the related art, and therefore the present disclosure is directed
to providing an apparatus for auto focus, which may continuously
maintain an AF carrier in a horizontal state and thus ensure better
reliability by configuring so that an attractive force generated
between a yoke and a magnet is sufficiently supported by balls even
though a mover (the AF carrier) moves up and down on the basis of
an optical axis direction by means of AF operation.
[0016] These and other objects and advantages of the present
disclosure may be understood from the following detailed
description and will become more fully apparent from the exemplary
embodiments of the present disclosure. Also, it will be easily
understood that the objects and advantages of the present
disclosure may be realized by the means shown in the appended
claims and combinations thereof.
Technical Solution
[0017] In one aspect of the present disclosure, there is provided
an apparatus for auto focus, comprising: a first frame having a
magnet; a second frame having an auto focus (AF) coil for moving
the first frame in an optical axis direction and a yoke giving an
attractive force to the magnet; and a plurality of balls arranged
in the optical axis direction and located between the first frame
and the second frame so that the first frame and the second frame
are maintained to be spaced apart from each other, wherein an
entire height of the plurality of balls is equal to or higher than
a height of the magnet on the basis of the optical axis
direction.
[0018] In addition, the plurality of balls may include a first ball
group having an n (n is a natural number of 3 or above) number of
balls arranged together along the optical axis direction; and a
second ball group having a m (m is a natural number of 3 or above)
number of balls provided at a location different from the first
ball group and arranged together along the optical axis direction,
wherein a height of all balls included in the first ball group or
the second ball group may be equal to or higher than the height of
the magnet on the basis of the optical axis direction.
[0019] Further, an uppermost ball which is a ball located at an
uppermost location in the first ball group or the second ball group
may be provided at a height equal to or higher than a top end of
the magnet on the basis of the optical axis direction. In this
case, the uppermost ball may have a center point at a height equal
to or higher than the top end of the magnet on the basis of the
optical axis direction.
[0020] More preferably, an outer circumference of a top end of the
uppermost ball may be located at a height equal to or higher than
the top end of the magnet, which is moved to an uppermost location
by means of auto focusing, on the basis of the optical axis
direction.
[0021] In addition, a lowermost ball which is a ball located at a
lowermost position in the first ball group or the second ball group
may be provided at a height equal to or lower than a bottom end of
the magnet on the basis of the optical axis direction. In this
case, the lowermost ball may have a center point at a height equal
to or lower than the bottom end of the magnet on the basis of the
optical axis direction.
[0022] More preferably, an outer circumference of a bottom end of
the lowermost ball may be located at a height equal to or lower
than the bottom end of the magnet, which is moved to a lowermost
location by means of auto focusing, on the basis of the optical
axis direction.
Advantageous Effects
[0023] According to an embodiment of the present disclosure, even
though a frame (or, an AF carrier) for AF moves forward or
rearwards in an optical axis direction on the basis of a base frame
(a housing, a stator, or the like) by means of AF operation, an
entire region where an attractive force is applied between the yoke
and the AF magnet is sufficiently supported by balls, and thus it
is possible to fundamentally prevent a tilt fault from being
generated due to the attractive force between the yoke and the AF
magnet.
[0024] According to an embodiment of the present disclosure, the AF
carrier may be always maintained in a horizontal state even though
AF operation is repeatedly performed, and thus it is possible to
more precisely control the AF operation and thus ensure better
reliability of the auto focus function.
[0025] In addition, the present disclosure may be optimally applied
to recent products and current technical trends in which more
sensitive responses are demanded even to a just tilt change of the
AF carrier due to slimmed components and higher-definition
pixels.
DESCRIPTION OF DRAWINGS
[0026] The accompanying drawings illustrate a preferred embodiment
of the present disclosure and together with the foregoing
disclosure, serve to provide further understanding of the technical
spirit of the present disclosure, and thus, the present disclosure
is not construed as being limited to the drawing.
[0027] FIG. 1 is a diagram showing an existing structure for AF
operation.
[0028] FIG. 2 is a schematic diagram for illustrating a tilt fault
generated in the existing AF operation.
[0029] FIG. 3 is an exploded perspective view showing an apparatus
for auto focus according to an embodiment of the present
disclosure.
[0030] FIG. 4 is a diagram showing detailed configurations of a
first frame and a second frame of the present disclosure, depicted
in FIG. 3.
[0031] FIG. 5 is a diagram showing configurations of balls and a
magnet according to an embodiment of the present disclosure.
[0032] FIG. 6 is a diagram showing that a tilt fault is prevented
during AF operation according to an embodiment of the present
disclosure.
BEST MODE
[0033] Hereinafter, preferred embodiments of the present disclosure
will be described in detail with reference to the accompanying
drawings. Prior to the description, it should be understood that
the terms used in the specification and the appended claims should
not be construed as limited to general and dictionary meanings, but
interpreted based on the meanings and concepts corresponding to
technical aspects of the present disclosure on the basis of the
principle that the inventor is allowed to define terms
appropriately for the best explanation.
[0034] Therefore, the description proposed herein is just a
preferable example for the purpose of illustrations only, not
intended to limit the scope of the disclosure, so it should be
understood that other equivalents and modifications could be made
thereto without departing from the scope of the disclosure.
[0035] FIG. 3 is an exploded perspective view showing an apparatus
100 for auto focus according to an embodiment of the present
disclosure.
[0036] As shown in FIG. 3, the apparatus 100 for auto focus
according to an embodiment of the present disclosure may include a
first frame 110, a second frame 120, an auto focus (AF) coil 121, a
yoke 125 and a plurality of balls 130.
[0037] A magnet 111 for AF operation is provided at the first frame
110, and a back yoke (not shown) for focusing a magnetic force may
be further installed at a rear surface of the magnet 111. The first
frame 110 is a component serving as a mover in the AF operation and
corresponds to the AF carrier described above.
[0038] In a device where only the AF function is solely
implemented, a lens (not shown) is loaded on the first frame 110 to
physically move together with the first frame 110. Thus, if the
first frame 110 moves in an optical axis direction, the lens also
moves in the optical axis direction (Z-axis direction), and by
means of this movement, a distance to an image sensor is adjusted,
thereby implementing the auto focus function.
[0039] In an embodiment where the AF function and the OIS function
are integrated, an optical image stabilization (OIS) frame (a
carrier) for OIS operation may be further provided at the first
frame 110 for the movement in an X-axis or Y-axis direction
perpendicular to the optical axis direction (Z).
[0040] In this case, in some embodiments, a lens (or, a lens
assembly) is loaded on the OIS frame (not shown). Here, if the
first frame 110 moves in the optical axis direction, the OIS frame
also moves together in the optical axis direction, and thus the
lens also moves in the optical axis direction. If the OIS operation
is performed to preventing hand-shaking, the OIS frame moves above
the first frame in a direction for compensating for the hand
shaking, for example in a direction perpendicular to the optical
axis direction.
[0041] The apparatus 100 for auto focus according to the present
disclosure is designed to effectively solve a tilt problem which
occurs during the AF operation and may be applied not only to a
device in which the AF function is solely implemented but also to a
device in which the AF function and the OIS function are integrally
implemented.
[0042] The second frame 120 of the present disclosure is a
counterpart of the first frame 110, and if the first frame 110 is a
mover in the AF operation, the second frame 120 corresponds to a
stator in a relatively point of view.
[0043] The second frame 120 may include an AF coil 121, a flexible
printed circuit board (FPCB) 123, a yoke 125, a hall sensor 127, a
drive chip 128 and so on. The AF coil 121 generates an
electromagnetic force corresponding to the intensity and direction
of power applied from the outside so that the first frame 110
having the magnet 111 moves in the optical axis direction.
[0044] The hall sensor 127 senses a location of the magnet 111 (a
location of the first frame, namely a location of the lens) by
means of a hall effect and transmits a corresponding signal to the
drive chip 128 of the present disclosure. The drive chip 128
controls power of suitable intensity and direction to be applied to
the AF coil 121 by using the signal input from the hall sensor.
[0045] In this way, an accurate location of the lens is fed back on
the basis of the optical axis direction, thereby implementing the
auto focus function. The AF coil 121, the drive chip 128 and the
hall sensor 127 are loaded on the FPCB 123 which is connected to an
external module, a power source, an external device or the
like.
[0046] As shown in FIG. 3, the second frame 120 may be composed of
a second sub-frame 120-1 and a second main frame 120-2 or may also
be implemented as a single integrated object.
[0047] As shown in FIG. 3, the plurality of balls 130 arranged in a
direction corresponding to the optical axis direction are located
between the first frame 110 and the second frame 120 (the second
sub-frame 120-1), and the first frame 110 and the second frame 120
are maintained to be spaced apart from each other as much as a
diameter of the balls by means of the plurality of balls 130.
[0048] The yoke 125 for generating an attractive force to the
magnet 111 provided at the first frame 110 is provided at the
second frame 120 in order to maintain a suitable interval between
the first frame 110 and the second frame 120 and also continuously
maintains point contacts between the first frame 110 and the
balls.
[0049] In this configuration, the first frame 110 and the second
frame 120 are adhered to each other with the balls 130 being
interposed therebetween by means of the attractive force applied
between the magnet 111 of the first frame 110 and the yoke 125 of
the second frame 120, and it may be regarded that the first frame
110 and the second frame 120 are physically supported by the balls
130.
[0050] Therefore, the configuration for generating a force to
adhere the first frame 110 and the second frame 120 to each other
and the configuration for physically making the first frame 110 and
the second frame 120 to contact each other are different from each
other.
[0051] In this configuration, as described above, if the first
frame 110 moves up and down by means of AF operation, the
attractive force between the magnet 111 and the yoke 125 is
generated depending on the location of the first frame 110 in a
region where the balls do not support, and due to this phenomenon,
a tilt fault is occurred at the first frame 110 which should be
maintained in a horizontal state.
[0052] The present disclosure is designed from the recognition of
this problem to overcome the problem, and as shown in FIG. 5, the
plurality of balls 130 are disposed between the first frame 110 and
the second frame 120, so that an entire height D1 of the plurality
of balls 130 is equal to or higher than a height D2 of the magnet
111 on the basis of the optical axis direction. In other words, the
height of the magnet 111 of the present disclosure is not higher
than the entire height of the plurality of balls 130.
[0053] If the entire height D1 of the balls 130 is equal to or
higher than the height D2 of the magnet 111 as described above, the
region where an attractive force is applied between the magnet 111
and the yoke 125 is covered by the balls 130 which physically
support the first frame 110 and the second frame 120, and thus a
tilt fault where the first frame 110 is inclined due to the
attractive force between the magnet 111 and the yoke 125 does not
occur.
[0054] FIG. 4 is a diagram showing detailed configurations of the
first frame 110 and the second frame 120 of the present
disclosure.
[0055] Since the first frame 110 of the present disclosure moves
forwards and rearwards along the optical axis direction as
described above, the plurality of balls 130 of the present
disclosure may be arranged along the optical axis direction (the
Z-axis direction) as shown in FIGS. 3 and 4 in order to effectively
guide the movement in the optical axis direction.
[0056] Further, in order to physically support the first frame 110
more stably by means of the point contacts, the plurality of balls
130 may be classified into a first ball group 130-1 having an n
number of balls arranged together along the optical axis direction
and a second ball group 130-2 having a m number of balls provided
at a location different from the first ball group 130-1 and
arranged together along the optical axis direction. Here, n and m
are natural numbers of 3 or above, and n and m may be identical to
or different from each other.
[0057] In this configuration, all balls included in the first ball
group 130-1 or the second ball group 130-2 are configured to have a
height equal to or higher than the height of the magnet 111 on the
basis of the optical axis direction.
[0058] In addition, a guide groove 113 extending along the optical
axis direction may be provided at the first frame 110 to prevent
the plurality of balls 130 from being deviated outwards and guide
the first frame 110 more effectively, and the guide groove 113 may
include a first guide groove 113-1 located at a left side and a
second guide groove 113-2 located at a right side based on FIG. 4,
as in the embodiment depicted in FIG. 4.
[0059] An accommodation groove 126 is provided at the second frame
120 to correspond to the structure of the guide groove 113 of the
first frame 110. Here, the accommodation groove 126 may include a
first accommodation groove 126-1 corresponding to the first guide
groove 113-1 of the first frame 110 and a second accommodation
groove 126-2 corresponding to the second guide groove 113-2 of the
first frame 110, namely disposed at a location to face the second
guide groove 113-2.
[0060] In this case, the first ball group 131-1 described above may
be provided to be partially accommodated between the first guide
groove 113-1 and the first accommodation groove 126-1, and the
second ball group 131-2 may be provided to be partially
accommodated between the second guide groove 113-2 and the second
accommodation groove 126-2.
[0061] Any one of the first guide groove 113-1 and the second guide
groove 113-2 may have a sectional shape of "V", and the other guide
groove may have a sectional shape of "U". If both guide grooves
have different shapes as above, contact portions with the balls and
rotation characteristics may be differently configured, which may
further improve the operation of the first frame 110 moving in the
optical axis direction.
[0062] As described above, the plurality of balls 130 according to
the present disclosure may be classified into the first ball group
130-1 and the second ball group 130-2. In this case, a ball located
at an uppermost location in the first ball group 130-1 or the
second ball group 130-2 may be provided at a height equal to or
higher than a top end of the magnet 111 on the basis of the optical
axis direction.
[0063] In the following description, a ball located at an uppermost
location in each of the first ball group 130-1 and the second ball
group 130-2 is called an uppermost ball, and relatively, a ball
located at a lowermost position in each of the first ball group
130-1 and the second ball group 130-2 is called a lowermost
ball.
[0064] If the uppermost ball is located at a height equal to or
higher than the top end of the magnet 111 as described above, the
entire region where the attractive force is generated between the
magnet 111 and the yoke 125, particularly the top region, may be
physically supported by the balls 130.
[0065] In order to physically support the first frame 110 and the
second frame 120 more effectively by means of the balls 130, as
shown in FIG. 5, the uppermost ball may be provided to have a
center point C1 at a height equal to or higher than a top end T on
the basis of the optical axis direction.
[0066] Similar to the uppermost ball described above, among the
plurality of balls 130 according to the present disclosure, the
lowermost ball may be provided at a height equal to or lower than a
bottom end of the magnet 111 on the basis of the optical axis
direction, and in order to physically support more effectively, as
shown in FIG. 5, the lowermost ball may have a center point C2 at a
height equal to or lower than the bottom end B of the magnet 111 on
the basis of the optical axis direction. In this case, the entire
height D1 of the balls 130 may also be equal to or higher than the
height D1 of the magnet 111.
[0067] FIG. 6(a) shows that the first frame 110, namely the magnet
111, moves to an uppermost position based on the optical axis by
means of AF operation, and FIG. 6(b) shows that the first frame
110, namely the magnet 111, moves to a lowermost position based on
the optical axis by means of AF operation.
[0068] If the magnet 111 is greater than the region (height) where
the balls 130 physically support, a tilt fault may occur at the
first frame 110 due to the attractive force between the magnet 111
and the yoke 125, as described above. This phenomenon becomes
gradually severe when the first frame 110 moves in both directions
along the optical axis by means of AF operation, and when the first
frame 110 moves to the maximum in both directions, a maximum tilt
fault may be generated.
[0069] In order to solve this problem, as shown in FIG. 6(a), the
uppermost ball 130 according to the present disclosure may be
configured so that an outer circumference BT (FIG. 6(a)) if its top
end is located at a height equal to or higher than the top end of
the magnet 111 when the first frame 110, namely the magnet 111,
moves to the uppermost location on the basis of the optical axis
direction by means of AF operation.
[0070] In addition, as shown in FIG. 6(b), the lowermost ball 130
according to the present disclosure may be configured so that an
outer circumference BB (FIG. 6(b)) of its bottom end is located at
a height equal to or lower than the bottom end of the magnet 111
when the magnet 111 moves to the lowermost location on the basis of
the optical axis direction by means of AF operation.
[0071] In this configuration, even though the magnet 111 moves up
or down (forwards or rearwards) in the optical axis direction
within a maximum range by means of AF operation, the entire where
an attractive force is applied between the magnet 111 and the yoke
125 is supported by the balls 130. Thus, it is possible to more
effectively prevent a tilt fault which becomes severe due to the
attractive force between the magnet 111 and the yoke 125.
[0072] The present disclosure has been described in detail.
However, it should be understood that the detailed description and
specific examples, while indicating preferred embodiments of the
disclosure, are given by way of illustration only, since various
changes and modifications within the scope of the disclosure will
become apparent to those skilled in the art from this detailed
description.
[0073] In the present disclosure, the terms such as "first" and
"second" are just used for distinguishing components from each
other and should not be interpreted as indicating special orders,
priorities or the like.
[0074] The drawings for illustrating the present disclosure may be
somewhat exaggerated to emphasize or highlight features of the
present disclosure, but it should be understood that various
modifications can be made in the level of those skilled in the art
in consideration of the above disclosure and the drawings.
REFERENCE SYMBOLS
TABLE-US-00001 [0075] 100: apparatus for auto focus 110: first
frame 111: magnet 120: second frame 121: coil 123: FPCB 125: yoke
127: hall sensor 128: drive chip 130: ball 130-1: first ball group
130-2: second ball group
* * * * *