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DESCRIPTION
[Title of Invention]
DRIVE UNIT, METHOD OF MANUFACTURING THE SAME, LENS
MODULE, AND IMAGE PICKUP UNIT
TECHNICAL FIELD
[0001] The present invention relates to a drive unit that uses a
predetermined actuator device, to a method of manufacturing the drive unit,
and to a lens module and an image pickup unit that include such a drive
unit.
BACKGROUND ART
[0002] Recently, mobile electronic apparatuses such as mobile phones,
personal computers (PC), and PDAs (personal digital assistants) have been
remarkably obtaining high functions and a mobile electronic apparatus is
typically provided with an image pickup function by providing a lens
module. Such mobile electronic apparatuses perform operation such as
focusing and zooming by allowing a lens in the lens module to travel along
an optical axis thereof.
[0003] It has been typical that movement of a lens in a lens module is
performed using, for example, a voice coil motor, a stepping motor, or the
like as a drive section. On the other hand, recently, those utilizing a
predetermined actuator device as the drive section have been developed in
terms of reducing size. Examples of such actuator devices include a
polymer actuator device (see Patent Literatures 1 and 2), a piezoelectric
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device, and a bimetal device. Out of these devices, the polymer actuator
device may be, for example, a device in which an ion-exchange resin film is
interposed between a pair of electrodes. In such a polymer actuator device,
a potential difference is generated between the pair of electrodes, and
thereby, the ion-exchange resin film is displaced in a direction
perpendicular to a film plane.
[Citation List]
[Patent Literature]
[0004] [Patent Literature 1] Japanese Unexamined Patent Application
Publication No. 2006-293006
[Patent Literature 2] Japanese Unexamined Patent Application
Publication No. 2006-172635
SUMMARY OF THE INVENTION
[0005] Typically, a drive unit using an actuator device as described
above is a cantilever actuator that drives a driving target by fixing a first
end portion (fixed portion) thereof and displacing a second end portion
(movable portion) thereof. In recent years, it has been desired to reduce
width (length in a direction perpendicular to a direction extending from the
first end toward the second end of the actuator device) of a cantilever as
much as possible, for example, in terms of freedom in design (size reduction
in structure) in such a cantilever actuator.
[0006] However, since it may be necessary to support the driving target
by the cantilever, it may be necessary to secure a certain width to allow the
actuator device to have sufficient strength (mechanical strength) to support
the driving target. Therefore, there has been a limit in reducing
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dimensions in a width direction of the cantilever. Accordingly, it has been
desired to propose a drive unit capable of reducing size while maintaining
drive characteristics.
[0007] The present invention has been made in view of the forgoing
issue and it is an object of the present invention to provide a drive unit
capable of reducing size while maintaining drive characteristics, a method
of manufacturing the drive unit, a lens module, and an image pickup unit.
[0008] A drive unit according to an embodiment of the present
invention includes: a fixing member; an actuator device having a first end
portion directly or indirectly fixed by the fixing member; and a reinforcing
member provided on part or all of the actuator device.
[0009] A lens module according to an embodiment of the present
invention includes: a lens; and the above-described drive unit according to
the embodiment of the present invention driving the lens.
[0010] An image pickup unit according to an embodiment of the present
invention includes: a lens; an image pickup device acquiring an image
pickup signal resulting from imaging by the lens; and the above-described
drive unit, driving the lens, according to the embodiment of the present
invention.
[0011] A method of manufacturing a drive unit according to an
embodiment of the present invention includes: forming an actuator device;
forming a reinforcing member on part or all of the actuator device; and
directly or indirectly fixing a first end portion of the actuator device by a
fixing member.
[0012] In the drive unit, the method of manufacturing the drive unit, the
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lens module, and the image pickup unit according to the embodiments of the
present invention, the reinforcing member is provided on part or all of the
actuator device. Therefore, mechanical strengthof the actuator device is
secured even when a width of the actuator device (length in a direction
perpendicular to a direction extending from the first end toward a second
end of the actuator device) is narrowed.
[0013] According to the drive unit, the method of manufacturing the
drive unit, the lens module, and the image pickup unit according to the
embodiments of the present invention, the reinforcing member is provided
on part or all of the actuator device. Therefore, mechanical strengthof the
actuator device is secured while setting the width of the actuator device to
be narrow. Therefore, size reduction is achievable while maintaining drive
characteristics.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] [FIG. 1] FIG. 1 is a schematic plan view illustrating an outline
configuration of a drive unit according to an embodiment of the present
invention.
[FIG. 2] FIG. 2 is a schematic view illustrating a side-face configuration
of the drive unit shown in FIG. 1.
[FIG. 3] FIG. 3 is a cross-sectional view illustrating a detailed
configuration of an actuator device (polymer actuator device) shown in FIG.
1.
[FIG. 4] FIG. 4 is a schematic cross-sectional view for explaining about
basic operation of the polymer actuator device shown in FIG. 3.
[FIG. 5] FIG. 5 is a schematic view illustrating an outline configuration
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and operation of a drive unit according to Comparative Example 1.
[FIG. 6] FIG. 6 is a schematic view illustrating an outline configuration
and operation of a drive unit according to Comparative Example 2.
[FIG. 7] FIG. 7 is a schematic plan view illustrating outline configurations
of drive units according to Modifications 1 and 2.
[FIG. 8] FIG. 8 is a schematic view illustrating an outline configuration
and operation of a piezoelectric device that functions as an actuator device
according to Modification 3.
[FIG. 9] FIG. 9 is a schematic view illustrating an outline configuration
and operation of a bimetal device that functions as an actuator device
according to Modification 4.
[FIG. 10] FIG. 10 is a perspective view illustrating a configuration
example of an electronic apparatus including an image pickup unit
according to Application Example 1 of the drive unit of any of the
embodiment and the modifications.
[FIG. 11] FIG. 11 is a perspective view illustrating the electronic
apparatus shown in FIG. 10 from a different direction.
[FIG. 12] FIG. 12 is a perspective view illustrating a main part
configuration of the image pickup unit shown in FIG. 11.
[FIG. 13] FIG. 13 is an exploded perspective view illustrating a lens
module shown in FIG. 12.
[FIG. 14] FIG. 14 is a schematic view illustrating a side-face configuration
and a planar configuration of the lens module shown in FIG. 12.
[FIG. 15] FIG. 15 is a cross-sectional view illustrating a detailed
configuration of part of actuator devices (polymer actuator devices), fixing
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members, and fixed electrodes shown in FIG. 13.
[FIG. 16] FIG. 12 is a side-face schematic view illustrating operation of
the lens module shown in FIG. 12.
[FIG. 17] FIG. 17 is a schematic view illustrating a side-face configuration
and a planar configuration of a lens module according to Modification 3.
[FIG. 18] FIG. 18 is a schematic view illustrating a side-face configuration
and a planar configuration of a lens module according to Application
Example 2.
[FIG. 19] FIG. 19 is a perspective view illustrating a method of
manufacturing a drive unit in the lens module shown in FIG. 18 in process
order.
[FIG. 20] FIG. 20 is a perspective view, a plan view, and a side-face view
each illustrating a process following a process shown in FIG. 19.
MODE(S) FOR CARRYING OUT THE INVENTION
[0015] An embodiment of the present invention will be described in detail
below with reference to the drawings. Description will be given in the
following order.
1. Embodiment (an example using a polymer actuator device as an actuator
device)
2. Modifications
Modifications 1 and 2 (examples in which a reinforcing layer has a
wide-width portion and a narrow-width portion)
Modification 3 (an example using a piezoelectric device as the actuator
device)
Modification 4 (an example using a bimetal device as the actuator
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device)
3. Application Examples 1 and 2 (examples in which a drive unit is applied
to a lens module and to an image pickup unit)
[0016]
[Embodiment]
[General Configuration of Drive Unit 1]
FIG. 1 schematically illustrates an outline configuration of a drive unit
(drive unit 1) according to an embodiment of the present invention in a plan
view (an X-Y plane view, a top view). Further, Part (A) of FIG. 2
schematically illustrates a side-face configuration (Z-X side-face
configuration) of the drive unit 1. Part (B) of FIG. 2 illustrates an enlarged
part of Part (A) of FIG. 2 (vicinity of a region designated by a symbol PI).
[0017] The drive unit 1 is a cantilever actuator that drives (along a Z
axis in this example) a driving target 9. The drive unit 1 includes a
supporting member 11, a fixing member 12, an actuator device 13, a
reinforcing layer 18 (reinforcing member), and a voltage supplying section
19.
[0018] The supporting member 11 is a base member (base) that supports
the drive unit 1 as a whole. The supporting member 11 is so arranged as to
extend on an XY plane in this example. The supporting member 11 may be
formed, for example, of a hard resin material such as a liquid crystal
polymer.
[0019] The fixing member 12 is a member that fixes a first end portion
(fixed portion) of the actuator device 13 and stands on the supporting
member 11 in a Z-axis direction. The fixing member 12 may also be
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formed, for example, of a hard resin material such as a liquid crystal
polymer.
[0020] The actuator device 13 is a device that drives the driving target
9 along the Z axis. The actuator device 13 is configured of a
flat-plate-like (thin-plate-like) polymer actuator device in this example.
In the actuator device 13, a length from the first end (closer to the fixing
member 12) to the second end (closer to the driving target 9, closer to the
movable portion) is LI. Further, concerning a width of the actuator device
13, a width Wll of a portion closer to the fixing member 12 is larger than a
width W12 of a portion closer to the driving target 9 in this example
(W11>W12). In other words, the actuator device 13 "has a wide-width
portion closer to the fixing member 12 and has a narrow-width portion
closer to the driving target 9. It is to be noted that description will be
given later of a detailed configuration of the actuator device 13 configured
of the polymer actuator device (FIG. 3).
[0021] The reinforcing layer 18 is a member that reinforces strength
(mechanical strength) of the actuator device 13 by being provided on part or
all of the actuator device 13. The reinforcing layer 18 is provided on both
a front face and a back face (a pair of main surfaces) of the actuator device
13 in this example. However, the reinforcing layer 18 may be provided on
one of the front and back faces of the actuator device 13- It is preferable
that the above-described reinforcing layer 18 be provided, for example, on
part or all of the above-described narrow-width portion (portion with the
width W12) of the actuator device 13. One reason for this is that the
narrow-width portion of the actuator device 13 contributes relatively a little
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to displacement (deformation) of the device as will be described later. The
reinforcing layer 18 is provided not only on the narrow-width portion of the
actuator device 13 but also on part or all of the above-described wide-width
portion (portion with the width Wll) in this example. Specifically, the
reinforcing layer 18 is continuously (integrally) provided from the
narrow-width portion over the wide-width portion of the actuator device 13.
The above-described reinforcing layer 18 may be formed, for example, of a
resin material such as polyimide (PI) and polyethylene naphthalate (PEN).
[0022] The voltage supplying section 19 supplies a drive voltage Vd to
the actuator device 13, and thereby drives (deforms) the actuator device 13.
The foregoing voltage supplying section 19 may include, for example, an
electric circuit that uses a component such as a semiconductor device. It is
to be noted that description will be given later of the detailed operation of
the voltage supplying section 19 driving the actuator device 13 (polymer
actuator device) (FIG. 4).
[0023]
[Detailed Configuration of Actuator Device 13]
Next, description will be given of a detailed configuration of the
actuator device 13 configured of the polymer actuator device with reference
to FIG. 3. FIG. 3 illustrates a cross-sectional configuration (Z-X
cross-section configuration) of the actuator device 13.
[0024] The actuator device 13 has a cross-sectional structure in which a
pair of electrode films 52A and 52B are formed on both faces of an ion
conductive polymer compound film 51 (hereinafter, simply referred to as
"polymer compound film 51"). In other words, the actuator device 13
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includes the pair of electrode films 52A and 52B and the polymer compound
film 51 inserted between the electrode films 52A and 52B. It is to be noted
that circumference of the actuator device 13 and of the electrode films 52A
and 52B may be covered with an insulating protection film formed of a
material with high elasticity (such as polyurethane).
[0025] The polymer compound film 51 curves in response to generation
of a predetermined potential difference between the electrode films 52A and
52B. The polymer compound film 51 is impregnated with an ionic
substance. "Ionic substance" herein refers to general ions that are movable
inside the polymer compound film 51. Specifically, "ionic substance"
herein refers to substances including a polar solvent and, for example, a
hydrogen ion, a simple substance of a metal ion, or a cation and/or an anion
thereof, and refers to substances including a cation and/or an anion being
liquid itself such as imidazolium salt. Examples of the former include
substances in which a polar solvent is solvated in a cation and/or an anion.
Examples of the latter include ionic liquid.
[0026] Examples of a material configuring the polymer compound film
51 includes an ion-exchange resin that includes, for example, a fluorine
resin or a hydrocarbon system as a skeleton thereof. As the ion-exchange
resin, a cation-exchange resin is preferable when the polymer compound
film 51 is impregnated with a cationic substance, and an anion-exchange
resin is preferable when the polymer compound film 51 is impregnated with
an anionic substance.
[0027] Examples of the anion-exchange resin include a resin to which
an acid group such as a sufonic acid group and a carboxyl group is
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introduced, in particular, polyethylene including an acid group, polystyrene
including an acid group, and a fluorine resin including an acid group. In
particular, a fluorine resin that includes a sulfonic acid group or a carboxyl
group is preferable as the cation-exchange resin, for example, Nafion
(available from E. I. du Pont de Nemours and Company).
[0028] The cationic substance that impregnates the polymer compound
film 51 may be any kind, for example, may be organic or inorganic.
Various materials may be used, for example, a simple substance of a metal
ion, a substance including a metal ion and water, a substance including an
organic cation and water, ionic liquid, etc. Examples of the metal ion
include light-metal ions such as a sodium ion (Na"^), a potassium ion (K^), a
lithium ion (Li"^), and a magnesium ion (Mg^"^). Moreover, examples of the
organic cation include an alkyl ammonium ion. The foregoing cations
exist as hydrates in the polymer compound film 51. Therefore, it is
preferable that the cationic substance be sealed as a whole so as to suppress
volatilization of water in the actuator device 13 when the polymer
compound film 51 is impregnated with a cationic substance including a
cation and water.
[0029] The ion liquid may be a so-called ambient-temperature molten
salt and includes a cation and an anion that have low burnability and low
volatility. Examples of the ionic liquid include imidazolium-ring-based
compounds, pirydinium-ring-based compounds, and aliphatic compounds.
[0030] In particular, the cationic substance preferably is ionic liquid since
ionic liquid has low volatility, and therefore, the actuator device 13
operates favorably even under high temperature atmosphere or in a vacuum.
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[0031] The electrode films 52A and 52B that face each other with the
polymer compound film 51 in between each include one or more conductive
materials. The electrode films 52A and 52B are each preferably formed of
conductive material powders bound together by an ion conductive polymer
since this increases flexibility of the electrode films 52A and 52B. The
conductive material powders are preferably carbon powders. One reason
for this is that a larger amount of deformation is obtainable since carbon
powders have high conductivity and large specific surface area. Ketjen
black is preferable as the carbon powders. Materials similar to those
configuring the polymer compound film 51 described above are preferable
as the ion conductive polymer.
[0032] The electrode films 52A and 52B may be formed as follows, for
example. That is, paint in which the conductive material powders and an
ion conductive polymer are dispersed in a dispersion medium is applied to
both faces of the polymer compound film 51 and is dried. Also, a film-like
component including the conductive material powders and the ion
conductive polymer may be crimped onto the both faces of the polymer
compound film 51.
[0033] The electrode films 52A and 52B each may have a multi-layer
structure. In this case, it is preferable that the electrode films 52A and
52B each have a structure in which a layer including the conductive
material powders bound by the ion conductive polymer and a metal layer are
laminated in order from the polymer compound film 51. This allows a
potential to be closer to a uniform value in an in-plane direction of the
electrode films 52A and 52B, and thereby, further superior deformation
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performance is obtained. Examples of a material configuring the metal
layer include noble metal such as gold and platinum. The metal layer may
have any thickness. However, the metal film is preferably a continuous
film so that a potential is uniform in the electrode films 52A and 52B.
Examples of a method of forming the metal film include plating, deposition,
and sputtering.
[0034] Dimensions (width and length) of the polymer compound film 51
may be appropriately set depending on factors such as the dimensions and
weight of the driving target 9 and displacement amount (deformation
amount) necessary in the polymer compound film 51. The displacement
amount of the polymer compound film 51 may be set, for example,
depending on the necessary displacement amount (moving amount along the
Z-axis direction) of the driving target 9.
[0035]
[Method of Manufacturing Drive Unit 1]
The drive unit 1 of the present embodiment may be manufactured as
follows, for example. That is, first, the actuator device 13 is formed.
Specifically, the actuator device 13 configured of the polymer actuator
device with the above-described structure is formed in this example.
[0036] Next, the reinforcing layer 18 configured of the foregoing
material is formed on part or all of the actuator device 13 by attaching the
reinforcing layer 18 thereto, for example, with use of an adhesive agent or
the like.
[0037] Subsequently, the first end portion of the actuator device 13 is
fixed by the fixing member 12 that stands on the supporting member 11.
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Further, a predetermined circuit (such as a semiconductor chip) configuring
the voltage supplying section 19 is also attached. Thus, the drive unit 1
shown in FIGs. 1 and 2 is completed.
[0038]
[Functions and Effects of Drive Unit 1]
Subsequently, description will be given of functions and effects of the
drive unit 1 of the present embodiment.
[0039]
[1. Operation of Actuator Device 13]
First, description will be given of operation of the actuator device 13
configured of the polymer actuator device with reference to FIG. 4. FIG. 4
schematically illustrates the operation of the actuator device 13 in a
cross-sectional view.
[0040] First, a case of using a substance including a cation and a polar
solvent as the cationic substance will be described.
[0041] In this case, the actuator device 13 without voltage application
does not curve and has a planar shape since the cationic substances are
dispersed almost uniformly in the polymer compound film 51 (Part (A) of
FIG. 4). Here, when the voltage supplying section 19 in Part (B) of FIG. 4
applies a voltage (begins application of a drive voltage Vd), the actuator
device 13 behaves as follows. That is, for example, when a predetermined
drive voltage Vd is applied between the electrode films 52A and 52B so that
the electrode film 52A has a minus potential and the electrode film 52B has
a plus potential, the cation moves toward the electrode film 52A with being
solvated with the polar solvent. At this time, the anion is hardly movable
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in the polymer compound film 51. Therefore, the electrode film 52A side
of the polymer compound film 51 is swollen and the electrode film 52B side
thereof is contracted. Accordingly, the actuator 13 as a whole curves
toward the electrode film 52B as shown in Part (B) of FIG, 4. Thereafter,
when a potential difference between the electrode films 52A and 52B is
eliminated to make a non-voltage application state (stop application of the
drive voltage Vd), the cationic substance (the cation and the polar solvent)
that has been tilted toward the electrode film 52A in the polymer compound
film 51 is diffused and returns to the state shown in Part (A) of FIG. 4.
Moreover, when a predetermined drive voltage Vd is applied between the
electrode films 52A and 52B in the non-voltage application state shown in
Part (A) of FIG. 4 so that the electrode film 52A has a plus potential and the
electrode film 52B has a minus potential, the cation moves toward the
electrode film 52B with being solvated with the polar solvent. In this case,
the electrode film 52A side of the polymer compound film 51 is contracted
and the electrode film 52B side thereof is swollen. Therefore, the actuator
device 13 as a whole curves toward the electrode film 52A.
[0042] Subsequently, a case of using ionic liquid including liquid
cation as the cationic substance will be described.
[0043] Also in this case, the actuator device 13 without voltage
application has the planar shape shown in Part (A) of FIG. 4 since the ionic
liquid is dispersed almost uniformly in the polymer compound film 51.
Here, when the voltage supplying section 19 applies a voltage (begins
application of a drive voltage Vd), the actuator device 13 behaves as
follows. That is, for example, when a predetermined drive voltage Vd is
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applied between the electrode films 52A and 52B so that the electrode film
52A has a minus potential and the electrode film 52B has a plus potential, a
cation in the ionic liquid moives toward the electrode film 52A. However,
the anion is not movable in the polymer compound film 51 which is a
cation-exchange film. Therefore, the electrode film 52A side of the
polymer compound film 51 is swollen and the electrode film 52B side
thereof is contracted. Accordingly, the actuator 13 as a whole curves
toward the electrode film 52B as shown in Part (B) of FIG. 4. Thereafter,
when a potential difference between the electrode films 52A and 52B is
eliminated to make a non-voltage application state (stop application of the
drive voltage Vd), the cation that has been tilted toward the electrode film
52A in the polymer compound film 51 is diffused and returns to the state
shown in Part (A) of FIG. 4. Moreover, when a predetermined drive
voltage Vd is applied between the electrode films 52A and 52B in the
non-voltage application state shown in Part (A) of FIG. 4 so that the
electrode film 52A has a plus potential and the electrode film 52B has a
minus potential, the cation in the ionic liquid moves toward the electrode
film 52B. In this case, the electrode film 52A side of the polymer
compound film 51 is contracted and the electrode film 52B side thereof is
swollen. Therefore, the actuator device 13 as a whole curves toward the
electrode film 52A.
[0044]
[2. Operation of Drive Unit 1]
In the drive unit 1, the driving target 9 is driven in accordance with the
above-described deformation (curve) of the actuator device 13.
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Accordingly, the driving target 9 becomes movable (displaceable) along the
Z axis as shown by an arrow in Part (A) of FIG. 2.
[0045] Here, functions and effects of the feature part of the drive unit 1
will be described in detail in comparison with comparative examples. FIG.
5 schematically illustrates an outline configuration and operation of a drive
unit (drive unit 101) according to Comparative Example 1. Part (A) shows
a planar configuration (X-Y plane configuration, top configuration) thereof
and Part (B) shows a side-face configuration (Z-X side-face configuration)
thereof. Further, FIG. 6 schematically illustrates an outline configuration
and operation of a drive unit (drive unit 201) according to Comparative
Example 2. Part (A) shows a planar configuration (X-Y plane
configuration, top configuration) thereof and Part (B) shows a side-face
configuration (Z-X side-face configuration) thereof.
[0046]
[Comparative Example 1]
First, the drive unit 101 of Comparative Example 1 shown in FIG. 5
does not include the reinforcing layer 18, unlike the drive unit 1 of the
present embodiment. Further, in the drive unit 101, an actuator device 103
has a width WlOl that is uniform (the same) from a portion closer to the
fixing member 12 over a portion closer to the driving target 9. In other
words, the width WlOl of the actuator device 103 as a whole is larger than
the width (in particular, the width W12 of the narrow-width portion) of the
actuator device 13 of the present embodiment (W101>W12).
[0047] In such a cantilever actuator, it is preferable to allow a width of
the cantilever to be as small as possible, for example, in a view of freedom
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in design (size reduction in structure). However, in the drive unit 101 of
Comparative Example 1, it is difficult to reduce the size of the structure (to
improve freedom in design) of the drive unit 101 as a whole since the width
WlOl of the actuator device 103 is large (wide).
[0048]
[Comparative Example 2]
On the other hand, in the drive unit 202 of Comparative Example 2
shown in FIG. 6, the actuator device 13 includes a wide-width portion (with
the width Wll) closer to the fixing member 12 and includes a narrow-width
portion (with the width W12) closer to the driving target 9 as in the drive
unit 1 of the present embodiment. Therefore, size reduction in the
structure (to improve freedom in design) of the drive unit 201 as a whole is
allowed, compared to the above-described drive unit 101 of Comparative
Example 1.
[0049] However, the drive unit 201 of Comparative Example 2 does not
include the reinforcing layer 18, unlike the drive unit 1 of the present
embodiment. Therefore, it is difficult to secure strength (mechanical
strength) of the actuator device 13 due to the small width (width W12) of
the cantilever. Therefore, there may be a case in which the actuator device
13 does not sufficiently drive (displace in a positive direction (upward
direction) of the Z axis, in this example) the driving target 9 as shown in
Part (B) of FIG. 6, for example. In other words, it is necessary to provide
the actuator device 13 with sufficient strength (mechanical strength) to
support the driving target 9 by securing a certain width since it is necessary
to support the driving target 9 by the cantilever.
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[0050] As described above, it is difficult to reduce size (improve
freedome in design) while maintaining (favorable) drive characteristics in
the above-described drive units 101 and 201 of Comparative Examples 1
and 2.
[0051] On the other hand, in the drive unit 1 of the present embodiment,
the reinforcing layer 18 is provided on part or all of the actuator device 13
as shown in FIGs. 1 and 2. Therefore, mechanical strengthof the actuator
device 13 is secured even when the width thereof (in particular, the width
W12 of the narrow-width portion) is narrowed.
[0052] Moreover, it can be said as follows concerning a location to
provide the reinforcing layer 18 in the drive unit 1 of the present
embodiment. That is, first, in the actuator device 13, the fixed portion
(see a region shown by the symbol Pll in Part (A) of FIG. 2) has larger
curvature than the movable portion (see a region shown by the symbol P12
in Part (A) of FIG. 2) at the time of deformation. Further, in view of
displacement enlarging effect due to the length of the beam, the fixed
portion contributes more to displacement at a tip (vicinity of the driving
target 9) of the actuator device 13 compared to the movable portion.
Therefore, it is the fixed portion that largely contributes to displacement
(deformation) of the actuator device 13, and a portion (such as the vicinity
of PI2) that contributes to the displacement relatively a little has small
influence on the displacement amount of the driving target 9 even if the
portion is restrained by the reinforcing layer 18. On the other hand,
generative force of the actuator device 13 increases in accordance with
(substantially in proportion to) increasing width (the width Wll of the
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wide-width portion in this example) of the fixed portion when rigidity
(flexural rigidity) of the cantilever actuator is sufficiently secured. As can
be said from the above, it is preferable to provide the reinforcing layer 18,
for example, on a middle portion (the vicinity of P12) or on the tip of the
cantilever with allowing the width Wll of the fixed portion (wide-width
portion) of the actuator device 13 to be sufficiently large. One reason is
that this allows setting the width W12 of the portion (narrow-width portion)
other than the fixed portion to be dramatically small while sufficiently
securing mechanical strength of the actuator device 13.
[0053] As described above, the reinforcing layer 18 is provided on part
or all of the actuator device 13 in the present embodiment.' Therefore,
mechanical strengthof the actuator device 13 is secured while setting the
width (in particular, the width W12 of the narrow-width portion) thereof to
be narrow. Therefore, size reduction is achievable while maintaining drive
characteristics and freedom in design is improved.
[0054] Moreover, the polymer actuator device is used in particular as
the actuator device 13. Therefore, the following advantages are obtainable
compared to a case of using an actuator device of other scheme (such as a
piezoelectric device and a bimetal device described later). That is, the
drive voltage Vd is suppressed to be low, and therefore, electric power
consumption is reduced. Also, low-cost manufacturing is achieved.
[0055]
[Modifications]
Subsequently, modifications (Modifications 1 to 4) of the
above-described embodiment will be described. It is to be noted that
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components same as those in the embodiment are designated by the same
numerals and description thereof will be appropriately omitted.
[0056]
[Modifications 1 and 2]
Part (A) of FIG. 7 schematically illustrates an outline configuration of
a drive unit (drive unit lA) according to Modification 1 in a plan view (X-Y
plane view, top view). Further, Part (B) of FIG. 7 schematically illustrates
an outline configuration of a drive unit (drive unit IB) according to
Modification 2 in a plan view (X-Y plane view, top view).
[0057] The drive unit lA of Modification 1 shown in Part (A) of FIG. 7
includes an actuator device 13A and a reinforcing layer 18A instead of the
actuator device 13 and the reinforcing layer 18, respectively, in the drive
unit 1 of the above-described embodiment. Other configurations of the
drive unit lA are similar to those of the drive unit 1 of the above-described
embodiment.
[0058] The actuator device 13A includes a wide-width portion (with the
width Wll) closer to the fixing member 12 and a narrow-width portion
(with the width W12) closer to the driving target 9, as the actuator device 13
of the above-described embodiment. Further, the reinforcing layer 18A
has a shape with a width in accordance with the narrow-width portion and
the wide-width portion of the actuator device 13A. In other words, the
reinforcing layer 18A also has a wide-width portion 18AI closer to the
fixing member 12 and includes a narrow-width portion 18A2 closer to the
driving target 9. It is to be noted that the planar shape of the wide-width
portion 18A1 is rectangular in this example.
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•
[0059] On the other hand, the drive unit IB of Modification 2 shown in
Part (B) of FIG. 7 includes an actuator device 13B and a reinforcing layer
18B instead of the actuator device 13 and the reinforcing layer 18,
respectively, in the drive unit 1 of the above-described embodiment. Other
configurations of the drive unit IB are similar to those of the drive unit 1 of
the above-described embodiment.
[0060] The actuator device 13B includes a wide-width portion (with the
width Wll) closer to the fixing member 12 and a narrow-width portion
(with the width W12) closer to the driving target 9, as the actuator device 13.
Further, the reinforcing layer 18B has a shape with a width in accordance
with the narrow-width portion and the wide-width portion of the actuator
device 13B. In other words, the reinforcing layer 18B also has a
wide-width portion 18B1 closer to the fixing member 12 and includes a
narrow-width portion 18B2 closer to the driving target 9. It is to be noted
that the planar shape of the wide-width portion 18B1 is triangular (a
triangular shape with a width gradually narrowed from the portion closer to
the fixing member 12 toward the portion closer to the driving target 9) in
this example.
[0061] As described above, in the Modifications 1 and 2, the
reinforcing layers 18A and 18B each have a shape with a width in
accordance with the narrow-width portion and the wide-width portion
thereof in the actuator devices 13A and 13B. Therefore, mechanical
strength of the actuator devices 13A and 13B are more easily secured even
when the driving target 9 is especially heavy.
[0062]
22
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[Modification 3]
FIG. 8 schematically illustrates, in a perspective view, an outline
configuration and operation of an actuator device (actuator device 13C)
applied to a drive unit according to Modification 3. The drive unit of the
present modification includes the actuator device 13C configured of a
piezoelectric device which will be described below, instead of the actuator
device 13 configured of the polymer actuator device described in the above
embodiment.
[0063] The piezoelectric device includes a conductive plate 61 that
extends on the X-Y plane, a pair of piezoelectric bodies 62A and 62B
arranged on both faces of the conductive plate 61, and a pair of fixing
members 63A and 63B that fix first end portions of the conductive plate 61
and of the piezoelectric bodies 62A and 62B.
[0064] The conductive plate 61 may be formed, for example, of a
material such as phosphor bronze. The piezoelectric bodies 62A and 62B
each may be formed, for example, of a piezoelectric material such as lead
zirconate titanate (PZT). It is to be noted that a predetermined
polarization process is performed on each of the piezoelectric bodies 62A
and 62B along a thickness direction thereof (Z-axis direction) and the
piezoelectric bodies 62A and 62B have the polarization directions that are
directed at the same direction.
[0065] The actuator device 13C configured of the piezoelectric device
with the above-described configuration operates as follows when a
predetermined drive voltage Vd is applied to each of the piezoelectric
bodies 62A and 62B. That is, one of the piezoelectric bodies (the
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piezoelectric body 62A in this example) extends along the X-axis direction,
and on the other hand, the other of the piezoelectric bodies (the
piezoelectric body 62B in this example) shrinks along the X-axis direction.
As a result, the actuator device 13C as a whole curves (is flexed) along the
thickness direction thereof (Z-axis direction) and generates a deformation
amount d in the Z-axis direction. It is to be noted that, when the polarity
of the drive voltage Vd is inversed, a deformation amount d in an opposite
direction is obtained in accordance thereto. Thus, the piezoelectric device
functions as the actuator device by supplying the drive voltage Vd.
[0066] Therefore, effects similar to those of the above-described
embodiment is obtained from functions similar to those of the
above-described embodiment also in the drive unit of the present
modification that uses the foregoing piezoelectric device as the actuator
device 13C.
[0067]
[Modification 4]
FIG. 9 schematically illustrates, in a side-face view (Z-X side-face
view), an outline configuration and operation of the actuator device
(actuator device 13D) applied to a drive unit according to Modification 4.
Part (A) illustrates a state before an operation and Part (B) illustrates a state
after the operation. The drive, unit of the present modification includes an
actuator device 13D configured of a bimetal device described below, instead
of the actuator device 13 configured of the polymer actuator device
described in the above embodiment.
[0068] The bimetal device includes a pair of metal plates (a
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high-expansion metal plate 72A and a low-expansion metal plate 72B
having different thermal expansion rates) that extend on the XY plane and a
pair of fixing members 73 A and 73B that fix first end portions of the metal
plates. The high-expansion metal plate 72A and the low-expansion metal
plate 72B are attached to each other to form a laminate structure.
[0069] The high-expansion metal plate 72A and the low-expansion
metal plate 72B each may be formed, for example, of a material in which
metal such as manganese (Mn), chromium (Cr), and copper (Cu) is added to
an alloy of iron (Fe) and nickel (Ni). The thermal expansion rates of the
high-expansion metal plate 72A and the low-expansion metal plate 72B are
differentiated by differentiating the amount of the foregoing metal added'to
the alloy.
[0070] When the actuator device 13D configured of the bimetal device
with the above-described configuration is brought into a high temperature
state compared to the flat state (before-operation state) shown in Part (A) of
FIG. 9, the high-expansion metal plate 72A expands more than the
low-expansion metal plate 72B. As a result, the actuator device 13D as a
whole curves (is flexed) along a thickness direction thereof (Z-axis
direction) and generates a deformation amount d in the Z-axis direction.
Therefore, the bimetal device functions as the actuator device by varying
temperature of the high-expansion metal plate 72A and the low-expansion
metal plate 72B with use of a heating section such as a heater which is not
illustrated.
[0071] Therefore, effects similar to those of the above-described
embodiment is obtained from functions similar to those of the
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above-described embodiment also in the drive unit of the present
modification that uses the foregoing bimetal device as the actuator device
13D.
[0072]
[Application Examples]
Subsequently, description will be given of application examples
(application examples to a lens module and to an image pickup unit:
Application Examples 1 and 2) of the drive units according to the
above-described embodiment and Modifications 1 to 4.
[0073]
[Application Example 1]
[Configuration of Mobile Phone 8]
FIGs. 10 and 11 each illustrate, in a perspective view, an outline
configuration of a mobile phone (mobile phone 8) with an image pickup
function as an example of an electronic apparatus with an image pickup unit
according to Application Example 1 of the drive unit of the above-described
embodiment and the like. In the mobile phone 8, two housings 81A and
8IB are connected to each other through an unillustrated hinge mechanism
in a foldable manner.
[0074] As shown in FIG. 10, a plurality of various operation keys 82 are
provided on a surface on one side of the housing 81A and a microphone 83
is provided on the bottom end of the housing 81A. The operation keys 82
receive predetermined operation by a user and are used to input information.
The microphone 83 is used to input voice of the user during phone call etc.
[0075] As shown in FIG. 10, a display section 84 using a liquid crystal
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display panel etc. is provided on a surface on one side of the housing BIB
and a speaker 85 is provided on the top end of the housing 81B. The
display section 84 may display, for example, various information such as
radio v^ave reception state, remaining amount of battery, a phone number of
a person who is on the phone, content stored in a phonebook (phone number,
name, etc. of a person), and lists of transmitted call and received call. The
speaker 85 outputs voice of the person on the phone etc. during the phone
call etc.
[0076] As shown in FIG. 11, a cover glass 86 is provided on a surface
on the other side of the housing 81A and an image pickup unit 2 is provided
in the housing 81A at a position corresponding to that of the cover glass 86.
The image pickup unit 2 includes a lens module 4 according to the present
application example that is arranged in a region closer to the object (cover
glass 86), and includes an image pickup device 3 arranged in a region closer
to an image (inside of the housing 81A). The image pickup device 3 is a
device that acquires an image pickup signal resulting from imaging by a
lens (later-described lens 40) in the lens module 4. The image pickup
device 3 is configured of an image sensor that is provided with, for example,
a charge coupled device (CCD), a complementary metal oxide
semiconductor (CMOS), or the like.
[0077]
[Configuration of Image Pickup Unit 2]
FIG. 12 illustrates, in a perspective view, a main part configuration of
the image pickup unit 2. FIG. 13 illustrates, in an exploded perspective
view, a configuration of the lens module 4 in the image pickup unit 2.
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Moreover, FIG. 14 schematically illustrates an outline configuration of the
lens module 4 with a side-face view (Z-X side-face view) in Part (A) and a
plan view (X-Y plane view) in Part (B).
[0078] The lens module 4 includes the supporting member 11, a
reinforcing layer 181, an actuator device 131, a lens holding member 14 and
a lens 40, reinforcing layer 182, and an actuator device 132 along an optical
axis Zl in order from the image (image pickup device 3) toward the object
(along the positive direction of the Z axis). It is to be noted that
illustration of the lens 40 is omitted in FIG. 12. The lens module 4 also
includes the fixing member 12, coupling members 15lA, 15IB, 152A, and
152B, fixed electrodes 130A and 130B, a steadying member 16, and hole
devices 17A and 17B. It is to be noted that the foregoing members of the
lens module 4 except for the lens 40 correspond to specific example of "lens
drive unit" of the present invention.
[0079] The supporting member 11 is a base material (base) that
supports the lens module 4 as a whole.
[0080] The fixing member 12 is a member that fixes a first end of each
of the actuator devices 131 and 132 in this example. The fixing member
12 includes three members, i.e., a lower fixing member 12D, a central
(middle) fixing member 12C, and an upper fixing member 12U that are
arranged from the image (bottom parts in FIGs. 12 and 13) toward the object
(upper parts in FIGs. 12 and 13). The first end of the actuator device 131
and first ends of the fixed electrodes 130A and 130B are interposed between
the lower fixing member 12D and the central fixing member 12C. On the
other hand, the first end of the actuator device 132 and second ends of the
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fixed electrodes 130A and 130B are interposed between the central fixing
member 12C and the upper fixing electrode 12U. Further, an opening
12C0 that allows a part of the lens holding member 14 (a part of a holding
portion 14B described later) to be partially inserted therethrough is formed
in the central fixing member 12C of the foregoing. This allows part of the
lens holding member 14 to move inside the opening 12C0. Therefore,
space is effectively utilized and the size of the lens module 4 is reduced.
[0081] The fixed electrodes 130A and 130B are electrodes that supply
the drive voltage Vd received from the foregoing voltage supplying section
19 to the electrode films (the foregoing electrode films 52A and 52B) in the
actuator devices 131 and 132. The fixed electrodes 130A and 130B may be
formed, for example, of gold (Au), metal plated with gold, etc. and has a
U-like shape. Therefore, the fixed electrodes 130A and 130B each
sandwich top and bottom of the central fixing member 12C (both side faces
along the Z axis) and is allowed to apply the same voltage in parallel to the
pair of actuator devices 131 and 132 with small number of wirings.
Further, degradation in contact resistance due to a factor such as surface
oxidation is prevented when the fixed electrodes 130A and 130B are
configured of a metal material plated with gold.
[0082] The lens holding member 14 is a member that holds the lens 40.
The lens holding member 14 may be formed, for example, of a hard resin
material such as liquid crystal polymer. The lens holding member 14 is so
arranged that the center thereof is on the optical axis Zl. The lens holding
member 14 includes the circular holding portion 14B that holds the lens 40,
and includes a connection portion 14A that supports the holding portion 14B
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# SP313830
and connects the holding portion 14B to the later-described coupling
members 151A, 15IB, 152A, and 152B. Moreover, the holding portion
14B is arranged between later-described driving faces of the pair of actuator
devices 131 and 132.
[0083] The actuator devices 131 and 132 each have a driving face (a
driving face on the X-Y plane) that is perpendicular to the optical axis Zl of
the lens 40. The actuator devices 131 and 132 are so arranged that the
driving faces face each other along the optical axis Zl. The actuator
devices 131 and 132 each drive the lens holding member 14 (and the lens
40) along the optical axis Zl through the later-described coupling members
151A, 151B, 152A, and 152B. Further, the actuator devices 131 and 132
are each configured of the foregoing polymer actuator device in this
example. The actuator devices 131 and 132 includes a wide-width portion
(with a width W21) closer to the fixing member 12 and a narrow-width
portion (with a width W22) in a movable portion (closer to the coupling
members 151A, 151B, 152A, and 152B) in this example as shown in Part
(B) of FIG. 14.
[0084] Here, as shown in a cross-sectional view (Z-X cross-section
view) in FIG. 15, in the actuator device 131, the electrode film 52A is
electrically connected to the fixed electrode 130B on the lower fixing
member 12D side thereof and the electrode film 52B is electrically
connected to the fixed electrode 130A on the central fixing member 12C
side thereof. On the other hand, in the actuator device 132, the electrode
film 52A is electrically connected to the fixed electrode 130A on the central
fixing member 12C side thereof, and the electrode film 52B is electrically
30
# SP313830
connected to the fixed electrode 130B on the upper fixing member 12U side
thereof. It is to be noted that, although not illustrated in FIG. 15, each of
the members and the electrodes from the fixed electrode 130B closer to the
lower fixing member 12D to the fixed electrode 130B closer to the upper
fixing member 12U is sandwiched and fixed by the steadying member 16
(plate spring) shown in FIG. 13 with a certain pressure. Accordingly, the
actuator devices 131 and 132 are not destroyed even when a large force is
applied thereto and stable electric connection is allowed even when the
actuator devices 131 and 132 are deformed.
[0085] The reinforcing layers 181 and 182 each correspond to the
reinforcing layer 18 described in the above embodiment and are selectively
provided on one face (back face) of the flat-plate-like actuator devices 131
and 132 in this example. However, the above-described reinforcing layers
181 and 182 may be provided on both faces (front face and back face) of the
actuator devices 131 and 132.
[0086] The coupling members 151A, 151B, 152A, and 152B are each a
member that couples (connects) an end of the connection portion 14A and
second ends of the respective actuator devices 131 and 132. Specifically,
the coupling members 151A and 151B each couple a lower end of the
connection portion 14A and the second end of the actuator device 131.
The coupling members 152A and 152B each couple an upper end of the
connection portion 14A and the second end of the actuator device 132.
The coupling members 151A, 151B, 152A, and 152B each may be formed,
for example, of a flexible film such as a polyimide film and is preferably
formed of a flexible material that has rigidity (flexural rigidity) almost
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equal to or less than (preferably, equal to or less than) that of the respective
actuator device 131 and 132. Accordingly, freedom of the coupling
members 151A, 151B, 152A, and 152B of curving in a direction opposite to
a curving direction of the actuator devices 131 and 132 is provided.
Therefore, a cross-sectional shape of the cantilever configured of the
actuator devices 131 and 132 and the coupling members 151A, 151B, 152A,
and 152B has an S-like curved line. As a result, the connection portion
14A is allowed to travel in parallel along the Z-axis direction and the
holding portion 14B (and the lens 40) is driven in the Z-axis direction with
maintaining a parallel state with respect to the supporting member 11. It is
to be noted that, for example, a spring constant may be used'as the
above-described rigidity (flexural rigidity).
[0087] Here, it is preferable that the following expression (1) is
satisfied where SI is rigidity (flexural rigidity) of the actuator devices 131
and 132, and S2 is rigidity (flexural rigidity) of the reinforcing layers 181
and 182. This allows the widths of the actuator devices 131 and 132 to be
set smaller and the size of the lens module 4 to be smaller. Further, it is
more preferable that the following expressions (2) and (3) are both satisfied
in addition to the expression (1) where S3 is rigidity (flexural rigidity) of
the coupling members 151A, 151B, 152A, and 152B. This allows the
widths of the actuator devices 131 and 132 to be set further smaller and the
size of the lens module 4 to be further smaller.
S2>S1 ...(1)
S2>S3 ...(2)
S1>S3 ...(3)
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# SP313830
[0088]
[Functions and Effects of Lens Module 4]
FIG. 16 illustrates, in a perspective view, operation of the lens module
4. Part (A) illustrates a state before an operation and Part (B) illustrates a
state after the operation.
[0089] In the lens module 4, as shown in Parts (A) and (B) of FIG. 16
(an arrow in the drawing), the pair of actuator devices 131 and 132 drive the
lens holding member 14, and thereby, the lens 40 is allowed to travel along
the optical axis Zl thereof. Thus, the lens 40 is driven along the optical
• axis Zl thereof by the drive unit (lens drive unit) that uses the actuator
devices 131 and 132, in the lens module 4.
[0090] Here, the reinforcing layers 181 and 182 are provided on part or
all of the actuator devices 131 and 132 also in the present application
example in a manner similar to that of the above-described embodiment.
Therefore, mechanical strength of the actuator devices 131 and 132 is
secured even when the widths (in particular, the width W22 of the
narrow-width portion) of the actuator devices 131 and 132 are narrowed as
shown in Part (B) of FIG. 14. Accordingly, the area of the actuator devices
131 and 132 is reduced, and therefore, an optical device with larger
diameter (the lens 40 with a large diameter Rl in this example) is allowed to
be provided in the lens module 4.
[0091] On the other hand, in a lens module (lens module 304) according
to Comparative Example 3 shown in Parts (A) and (B) of FIG. 17, the
reinforcing layer as in the present application example is not provided.
Therefore, an area of an actuator device 302 is large. Specifically, the
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wide-width portion (with a width W301) closer to the fixing member 12 and
the narrow-width portion (with a width W302) in a movable portion (closer
to the coupling members 151A, 151B, 152A, and 152B) are larger than the
widths W21 and W22 of the actuator devices 131 and 132. Therefore, a
diameter of the optical device (a diameter R301 of a lens 340 in this
example) is smaller in the lens module 304 according to Comparative
Example 3 compared to in the lens module 4 of the present application
example (R1>R301). In other words, it is difficult to provide an optical
device with a large diameter in the lens module 304 in Comparative
Example 3.
[0092]
[Application Example 2]
[Configuration of Lens Module 4A]
FIG. 18 schematically illustrates an outline configuration of a lens
module 4A according to Application Example 2 in a side-face view (Z-X
side-face view) in Part (A) and in a plan view (X-Y plane view) in Part (B).
The lens module 4A of the present application example includes reinforcing
layers 181A, 181B, 182A, and 182B instead of the reinforcing layers 181
and 182 in the lens module 4 of the above-described Application Example 1.
Moreover, in the lens module 4A, a length of the coupling members 151A,
15IB, 152A, and 152B in the X-axis direction is set to be longer than the
length (length in the X-axis direction) of the beam of the actuator devices
131 and 132, unlike in the above-described Application Example 1.
[0093] The reinforcing layers 181A, 181B, 182A, and 182B correspond
to the reinforcing layer 18 described in the above-embodiment and are
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SP313830
provided on both surfaces (front and back faces) of the flat-plate-like
actuator devices 131 and 132 in this example.
[0094]
[Method of Manufacturing Lens Drive Unit in Lens Module 4A]
Lens drive unit part (the actuator devices 131 and 132, the coupling
members 151A, 151B, 152A, and 152B, and the reinforcing layers 181A,
181B, 182A, and 182B) out of those in the lens module 4A of the present
application example, in particular, may be manufactured as follows. FIGs.
19 and 20 illustrate an example of processes of manufacturing the lens drive
unit part in perspective views, a plan view (X-Y plane view), and a
side-face view (Z-X side-face view).
[0095] First, as shown in Part (A) of FIG. 19, an actuator device 130
configuring the actuator devices 131 and 132 and a low-rigidity layer 150
(for example, a layer formed of the foregoing materials exhibiting rigidity
S3) configuring the coupling members 151A, 151B, 152A, and 152B are
arranged with a predetermined space.
[0096] Subsequently, as shown in Part (B) of FIG. 19, a high-rigidity
layer 180A (for example, a layer formed of the foregoing materials
exhibiting rigidity S2) configuring the reinforcing layers 181A and 182A is
attached on one surface (front face) of the actuator device 130 and the
low-rigidity layer 150 with use of, for example, an adhesive agent or the
like. Subsequently, as shown in Part (C) of FIG. 19, a high-rigidity layer
180B (for example, a layer made of the foregoing materials exhibiting
rigidity S2) configuring the reinforcing layers 181B and 182B is attached on
the other surface (back face) of the actuator device 130 and the low-rigidity
35
# SP313830
t
layer 150 with use of, for example, an adhesive agent or the like in a similar
manner. Thus, the high-rigidity layers 180A and 180B configuring the
reinforcing layer are formed on the actuator device 130.
[0097] Thereafter, a region shown by a dashed line in Part (A) of FIG.
20 is mechanically cut out, for example, by a process using, for example, a
punch, a laser beam, or the like. In other words, the actuator device 130,
the low-rigidity layer 150, and the high-rigidity layers 180A and 180B are
cut out in a predetermined shape. Accordingly, the lens drive unit in the
lens module 4A shown in FIG. 18 is completed as shown in Part (B) of FIG.
20.
[0098] Effects similar to those' of the above-described Application
Example 1 is obtained from functions similar to those of the
above-described Application Example 1 also in the lens module 4A of the
present application example with the above-described configuration. In
other words, the area of the actuator devices 131 and 132 is reduced, and
therefore, an optical device with a larger diameter (the lens 40 with a large
diameter Rl) is allowed to be provided in the lens module 4A.
[0099]
[Other Modifications]
The present invention has been described hereinabove with referring to
the embodiment, the modifications, and the application examples as
examples. However, the present invention is not limited to the
above-described embodiments and the like and may be variously modified.
[0100] For example, the connection portion 14A and the coupling
members 151A, 151B, 152A, and 152B that are described in the above
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embodiment and the like may not be provided in some cases. Moreover,
description has been given in the above embodiment and the like of a case
in which the first end portion of the actuator device is directly fixed by the
fixing member; however, this is not limitative. In other words, the first
end portion of the actuator device may be indirectly (through a component
such as a fixed electrode) fixed by the fixing member.
[0101] Moreover, description has been mainly given in the above
embodiment and the like of a case in which a pair of actuator devices are
provided. However, the actuator devices are not necessarily one pair, and
one, or three or more actuator devices may be provided.
[0102] Moreover, the shape of each actuator device is not limited to
those described in the above embodiment and the like. The laminate
configuration of each actuator device is also not limited to those described
in the above embodiment and the like and may be appropriately changed.
Moreover, for example, a shape, a material, etc. of each member in the lens
module (drive unit) are not limited to those described in the above
embodiment and the like. For example, the shape of the reinforcing
member is not limited to the shapes (such as a layered structure (reinforcing
layer)) described in the above embodiment and the like, and may be other
shapes.
[0103] In addition, the lens drive unit that drives the lens along the
optical axis thereof has been described as an example of the drive unit of
the present invention in the above embodiment and the like. However, it is
not limited to the case, and the lens drive unit may drive the lens along a
direction perpendicular to the optical axis thereof, for example. Moreover,
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4
the drive unit of the present invention is applicable to those other than the
above-described lens drive unit, such as a drive unit that drives an aperture
etc. (see Japanese Unexamined Patent Application Publication No.
2008-259381 etc.). Moreover, the drive unit, the lens module, and the
image pickup unit of the present invention are applicable to various
electronic apparatuses other than the mobile phone described in the above
embodiment and the like.
38

4i SP313830
CLAIMS
1. A drive unit comprising:
a fixing member;
an actuator device having a first end portion directly or indirectly
fixed by the fixing member; and
a reinforcing member provided on part or all of the actuator device.
2. The drive unit according to claim 1, wherein
the actuator device includes a wide-width portion in the first end
portion and includes a narrow-width portion in a second end portion; and
the reinforcing member is provided on part or all of the
narrow-width portion.
3. The drive unit according to claim 2, wherein the reinforcing member
is provided also on part or all of the wide-width portion.
4. The drive unit according to claim 3, wherein the reinforcing member
is provided continuously from the narrow-width portion over the
wide-width portion.
5. The drive unit according to claim 4, wherein the reinforcing member
has a shape with a width in accordance with the narrow-width portion and
the wide-width portion of the actuator device.
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6. The drive unit according to any one of claim 1 to claim 5, wherein
the drive unit is a lens drive unit driving a lens.
7. The drive unit according to claim 6, further comprising:
a lens holding member holding the lens; and
a coupling member coupling the second end portion of each of a
plurality of the actuator devices and an end of the lens holding member,
wherein
the plurality of the actuator devices each having a driving face
perpendicular to an optical axis of the lens are arranged to allow the driving
faces to face each other along the optical axis of the lens, and
the first end portion of each of the plurality of the actuator devices
is fixed by the fixing member.
8. The drive unit according to claim 7, wherein S2>S1 is satisfied
where SI is rigidity of the actuator devices and 82 is rigidity of the
reinforcing member.
9. The drive unit according to claim 8, wherein S2>S3 and S1>S3 are
further satisfied where S3 is rigidity of the coupling member.
10. The drive unit according to claim 7, wherein
the lens holding member includes
a holding portion holding the lens, and
a connection portion supporting the holding portion and connecting
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the holding portion to the coupling member, and
the holding portion is arranged between the driving faces of the
actuator devices.
11. The drive unit according to claim 10, wherein an opening allowing
the holding portion to be partially inserted therethrough is formed in the
fixing member.
12. The drive unit according to any one of claim 1 to claim 5, wherein
S2>S1 is satisfied where SI is rigidity of the actuator device and S2 is
rigidity of the reinforcing member.
13. The drive unit according to any one of claim 1 to claim 5, wherein
the actuator device has a flat-plate-like shape having a pair of main
surfaces that face each other, and
a reinforcing layer is provided as the reinforcing member on one or
both of the pair of main surfaces.
14. The drive unit according to any one of claim 1 to claim 5, wherein
the actuator device is a polymer actuator device.
15. The drive unit according to claim 14, wherein
the polymer actuator device includes
a pair of electrode films, and
a polymer film inserted between the pair of electrode films.
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16. The drive unit according to any one of claim 1 to claim 5, wherein
the actuator device is one of a piezoelectric device and a bimetal device.
17. A lens module comprising:
a lens; and
a drive unit driving the lens, wherein
the drive unit includes
a fixing member,
an actuator device having a first end portion directly or indirectly
fixed by the fixing member, and
a reinforcing member provided on part or all of the actuator device.
18. An image pickup unit comprising:
a lens;
an image pickup device acquiring an image pickup signal resulting
from imaging by the lens; and
a drive unit driving the lens, wherein
the drive unit includes
a fixing member,
an actuator device having a first end portion directly or indirectly
fixed by the fixing member, and
a reinforcing member provided on part or all of the actuator device.
i
19. A method of manufacturing a drive unit, the method comprising:
42
SP313830
forming an actuator device;
forming a reinforcing member on part or all of the actuator device;
and
directly or indirectly fixing a first end portion of the actuator device
by a fixing member.
20. The method according to claim 19, wherein
the forming of the reinforcing member includes
forming a reinforcing layer on the actuator device, and
cutting each of the actuator device and the reinforcing layer into a
predetermined'shape.