WO2023245483A1

WO2023245483A1 - Mechanism to supply current to electric component

Info

Publication number: WO2023245483A1
Application number: PCT/CN2022/100372
Authority: WO
Inventors: Kazuhiro Hattori; Kazuki SAKAE; Hiroshi Ariga; Fuwei ZHANG
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2022-06-22
Filing date: 2022-06-22
Publication date: 2023-12-28

Abstract

A lens module comprises a movable unit and a fixed unit of an actuator, wherein the actuator is configured to drive the movable unit by an interaction, caused by supplying a current to the movable unit, between the movable unit and the fixed unit. A conductive member (109, 110) provided on the movable unit is movably in contact with a conductive member (105, 106) fixed in position to the fixed unit for receiving a supply of current. This saves the number of parts used for current supply, and allows reduction in size.

Description

MECHANISM TO SUPPLY CURRENT TO ELECTRIC COMPONENT

TECHNICAL FIELD

Embodiments of the present application generally relate to electric components, and in particular, to a mechanism to supply electric current to components mounted on a movable unit.

BACKGROUND

Today, many devices including mobile or portable devices are equipped with camera modules. As used herein, camera modules may refer to camera modules in dedicated mobile cameras as well as camera modules in mobile devices such as smartphones, mobile phones, tablet computers, laptop computers or the like.

Camera modules typically comprises one or more lens groups movable for focusing or zooming purposes. Moving of a lens or a lens group is generally achieved by an actuator.

One known actuator comprises a linear motor comprising a fixed unit and movable unit, in which electromagnetic interaction between a coil and a magnet drives the movable unit to move. There are two types of such an actuator depending on whether an electric component which needs to be supplied with electric current (e.g., a coil) is mounted on a fixed unit or a on a movable unit. A design with a coil mounted on a movable unit may be called a moving-coil design, whereas a design with a coil mounted on a fixed unit may be called a moving-magnet design.

The moving-coil design is advantageous in that the weight of the movable unit may be reduced. This is because typically coils are less weighty than magnets. On the other hand, the moving-coil design requires some mechanism to supply electric current to the movable unit.

In recent years, with emergence of smaller camera modules, smaller actuators are desired. Moreover, a longer stroke of the movable lens group is desired as tele lenses are becoming standard equipment. A longer stroke is also desirable for achieving a larger range of focal length or zoom ratio.

In a first possible embodiment of an actuator, electric current is supplied to a movable unit via a leaf spring, wherein the leaf spring also serves as a mechanical support for a movable lens group. This may allow reduction of size by employing a member for a mechanical support of the moveable unit also as a means to supply electric current to the moveable unit of the actuator. Such a design may be used for wide-angle lenses.

However, such an embodiment is not suitable for a long stroke. A large displacement of the movable lens group increases internal stress within the leaf spring. In order to prevent breaking of the leaf spring or prevent decrease of its lifetime due to too large an internal stress, the stroke needs to be within in a certain range.

In a second possible embodiment of an actuator, electric current is supplied to a moveable unit via a flexible printed circuit (FPC) . A flexible printed circuit comprises one or more conductors placed on a (typically thin) dielectric film or board or sandwiched between such dielectric films or boards so that FPC can be bent or folded. Such an embodiment with FPC is useful in camera modules with a relatively long stroke of a moveable lens group.

However, such an embodiment may result in (i) a large size of a camera module in order to accommodate folded FPC; (ii) loss of a driving force of the actuator (that is, lower efficiency) due to reaction forces of the FPC; and (iii) increased complexity in assembling (that is, reduced assemblability) .

Some of the above-mentioned problems may be solved by a design in which an electric component which needs to be supplied with electric current (e.g., a coil) is mounted on a fixed unit rather than on a movable unit (e.g., a moving-magnet design) . However, such a design requires a weighty component such as a magnet to be mounted on the moveable unit, which results in a loss of driving force of the actuator or an increased size of the actuator, and hence the camera module, to compensate for such a loss.

SUMMARY

The present disclosure aims to provide a mechanism for supplying electric current to a movable component that addresses one or more of the above-mentioned issues.

According to a fist aspect of the present disclosure, a lens module is provided. In an implementation, the lens module comprises a movable unit and a fixed unit of an actuator. The actuator is configured to drive the movable unit by an interaction, caused by supplying a current to the movable unit, between the movable unit and the fixed unit. A conductive member provided on the movable unit is movably in contact with a conductive member fixed in position to the fixed unit for receiving a supply of current.

Since the conductive member provided on the movable unit is movably in contact with the conductive member fixed in position to the fixed unit for receiving a supply of current, FPC is not necessary for supplying current, which eliminates the need of space for accommodating folded FPC, and thus allows a smaller size of the lens module. Moreover, since loss of driving force by reaction force of FPC is not incurred, its efficiency is not lost. Furthermore, since this does not rely on a leaf spring, a long stroke is allowed.

In one possible implementation of the first aspect of the present disclosure based on the above-mentioned implementation of the first aspect, the conductive member provided on the movable unit is movably in contact via bearing with the conductive member fixed in position to the fixed unit for receiving a supply of current.

The conductive member provided on the movable unit being movably in contact with the second conductive member via bearing provides an advantageous embodiment of the movable contact.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the conductive member provided on the movable unit comprises a conductive plate; wherein the conductive member fixed in position to the fixed unit comprises a conductive guide shaft that can be coupled to a current supply; wherein the guide shaft is configured to guide the movable unit to allow movement in a direction along the guide shaft.

Many lens modules comprise guide shafts. Use of existing guide shafts for supplying current to the movable unit saves the number of components, which in turn allows a smaller size of the lens module.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the conductive member provided on the movable unit comprises a first conductive plate and a second conductive plate; wherein the conductive member fixed in position to the fixed unit comprises a first guide shaft that can be coupled to an electrode of a first polarity of a current supply and a second guide shaft that can be coupled to an electrode of a second polarity of the current supply; wherein the first guide shaft and the second guide shaft are configured to guide the movable unit to allow movement in a direction along the guide shafts; wherein the first conductive plate is movably in contact with the first guide shaft via first bearing made of a conductive material; and wherein the second conductive plate is movably in contact with the second guide shaft via second bearing made of a conductive material.

The conductive plates being movably in contact with the guide shafts via bearing provides an advantageous embodiment of the movable contact. Many lens modules comprise guide shafts. Use of existing guide shafts for supplying current to the movable unit saves the number of components, which in turn allows a smaller size of the lens module.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the interaction between the movable unit and the fixed unit is an electromagnetic interaction between a coil provided on the movable unit and a magnet provided on the fixed unit; wherein a first end of the coil is coupled to the first conductive plate, and a second end of the coil is coupled to the second conductive plate; and wherein a current path is formed through the first guide shaft, the first bearing, the first conductive plate, the coil, the second conductive plate, the second bearing, and the second guide shaft.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the movable unit comprises a holder; wherein the first guide shaft is inserted in the first bearing provided inside a first opening of the holder, wherein an inner diameter of the first bearing substantially matches an outer diameter of the first guide shaft; and wherein the second guide shaft is inserted in the second bearing provided inside a second opening of the holder, wherein an inner diameter of the second bearing substantially matches an outer diameter of the second guide shaft.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the first conductive plate and the second conductive plate are provided on the holder by insert molding.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, a gap between the first bearing and the first guide shaft and/or a gap between the second bearing and the second guide shaft are filled with a conductive grease.

Use of a conductive grease makes more reliable electric conductivity between the bearing and the guide shaft. While a conductive grease per se is known, it is usually used for discharge static electricity. The inventors of the present application realized that such a conductive grease may be used in the context of supplying current.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the conductive member provided on the movable unit comprises a first conductive plate and a second conductive plate; wherein the conductive member fixed in position to the fixed unit comprises a first portion and a second portion of a first guide shaft, wherein the first portion and the second portion of the first guide shaft are mechanically coupled via a non-conductive joint; wherein the first guide shaft and a second guide shaft are configured to guide the movable unit to allow movement in a direction along the guide shafts; wherein the first conductive plate is movably in contact with the first portion via first bearing made of a conductive material; and wherein the second conductive plate is movably in contact with the second portion via second bearing made of a conductive material.

The conductive plates being movably in contact with the respective portions of the guide shaft via bearing provides an advantageous embodiment of the movable contact. Many lens modules comprise guide shafts. Use of existing guide shafts for supplying current to the movable unit saves the number of components, which in turn allows a smaller size of the lens module.

Moreover, when compared with the embodiment that employs two guide shafts for supplying electric current to the movable unit, the arrangement of components for current supply around one guide shaft allows further reduction in size and simplification in the actuator.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the interaction between the movable unit and the fixed unit is an electromagnetic interaction between a coil provided on the movable unit and a magnet provided on the fixed unit; wherein a first end of the coil is coupled to the first conductive plate, and a second end of the coil is coupled to the second conductive plate; and wherein a current path is formed through the first portion of the first guide shaft, the first bearing, the first conductive plate, the coil, the second conductive plate, the second bearing, and the second portion of the first guide shaft.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the movable unit comprises a holder; wherein the first guide shaft is inserted in the first bearing provided inside a first opening of the holder and the second bearing provided inside a second opening of the holder, wherein an inner diameter of the first bearing and an inner diameter of the second bearing substantially match an outer diameter of the first guide shaft.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, wherein the first conductive plate and the second conductive plate are provided on the holder by insert molding.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, a gap between the first bearing and the first portion of the first guide shaft and/or a gap between the second bearing and the second portion of the first guide shaft are filled with a conductive grease.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the conductive member provided on the movable unit comprises a first conductive plate and a second conductive plate; wherein the conductive member fixed in position to the fixed unit comprises a first conductive pattern and a second conductive pattern provided on the fixed unit, wherein the first conductive plate is movably in contact with the first conductive pattern; and wherein the second conductive plate is movably in contact with the second conductive pattern.

The conductive plates being movable in contact with conductive patterns provides an advantageous embodiment of the movable contact. Moreover, this embodiments eliminates the bearing of the first and second embodiments, which allows further simplification in the actuator. Still, FPC is not necessary for supplying current, which eliminates the need of space for accommodating folded FPC, and thus allows a smaller size of the lens module. Moreover, since loss of driving force by reaction force of FPC is not incurred, its efficiency is not lost.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the interaction between the movable unit and the fixed unit is an electromagnetic interaction between a coil provided on the movable unit and a magnet provided on the fixed unit; wherein a first end of the coil is coupled to the first conductive plate, and a second end of the coil is coupled to the second conductive plate; and wherein a current path is formed through the first conductive pattern, the first conductive plate, the coil, the second conductive plate, and the second conductive pattern.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the first conductive pattern and the second conductive pattern are provided in a FPC (flexible printed circuit) substantially unbendably attached to the fixed unit.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the end portion that is of the first conductive plate and that is movably in contact with the first conductive pattern and/or the end portion that is of the second conductive plate and that is movably in contact with the second conductive pattern are brush-shaped.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the movable unit comprises a holder, wherein the first conductive plate and the second conductive plate are provided on the holder by insert molding.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, one or more guide shafts provided fixed in position to the fixed unit are configured to guide the movable unit to allow movement in a direction along the one or more guide shafts.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the movable unit comprises a lens group comprising one or more lenses and a lens frame that holds the lens group, wherein the movable unit is driven in a direction parallel to an optical axis of the lens group.

In one possible implementation of the first aspect of the present disclosure based on any suitable one of the above-mentioned implementations of the first aspect, the movable unit comprises a lens group comprising one or more lenses and a lens frame that holds the lens group, wherein the movable unit is driven in a direction parallel to an optical axis of the lens group, and wherein the lens frame is integral with the holder.

According to a second aspect of the present disclosure, a camera module is provided. The camera module may comprise the lens module based on any suitable one of the above-mentioned implementations of the first aspect of the present disclosure; and an image sensor.

According to a third aspect of the present disclosure, an electronic device is provided. The electric device may comprise the camera module according to the second aspect of the present disclosure.

In one possible implementation of the third aspect of the present disclosure, the electronic device may be a smartphone or a mobile phone.

According to a fourth aspect of the present disclosure, a method for driving an actuator comprising a movable unit and a fixed unit is provided. A conductive member provided on the movable unit is movably in contact with a conductive member fixed in position to the fixed unit. The method comprises: supplying a current, from a current supply electrically coupled to the fixed unit, to the conductive member fixed in position to the fixed unit; conveying the current, from the conductive member fixed in position to the fixed unit, via movable contact, to a conductive member provided on the movable unit; and driving the movable unit by an interaction, caused by supplying a current to the movable unit, between the movable unit and the fixed unit.

In one possible implementation of the fourth aspect of the present disclosure, the interaction between the movable unit and the fixed unit is an electromagnetic interaction between a coil provided on the movable unit and a magnet provided on the fixed unit.

Various features including those described for the lens modules in the above are also applicable for method embodiments. Details are not repeated here. Since the advantages of this embodiment are also similar to those of the first embodiment, they are not repeated here for the sake of simplicity.

According to a fifth aspect of the present disclosure, a component comprising a mechanism for supplying a current from a fixed unit to a movable unit is provided. A conductive member provided on the movable unit is movably in contact with a conductive member fixed in position to the fixed unit for receiving a supply of current.

Various features including those described for the lens modules in the above are also applicable for method embodiments. Details are not repeated here. Since the advantages of this embodiment are similar to those of the first embodiment, they are not repeated here for the sake of simplicity.

BRIEF DESCRIPTION OF DRAWINGS

For a more complete understanding of the present disclosure, reference is now made to the following drawings. It should be noted that illustration of more than one component in one drawing does not necessarily mean that those components need to be provided together. Necessary components of an invention are defined only by the recitations in the claims.

FIG. 1A is a schematic diagram for illustrating a lens module according to a first embodiment of the present disclosure; FIG. 1B illustrates in detail first and second guide shafts and first and second conductive plates of the lens module according to the first embodiment of the present disclosure;

FIG. 2A is a schematic diagram for illustrating a lens module according to a second embodiment of the present disclosure; FIG. 2B is a schematic diagram for illustrating a rear view of the lens module according to the second embodiment of the present disclosure; FIG. 2C illustrates in detail first and second portions of a first guide shaft and first and second conductive plates of the lens module according to the second embodiment of the present disclosure;

FIG. 3A is a schematic diagram for illustrating a lens module according to a third embodiment of the present disclosure; FIG. 3B is a schematic diagram for illustrating a rear view of the lens module according to the third embodiment of the present disclosure;

FIG. 4A and FIG. 4B are schematic cross-sectional diagrams for illustrating application of conductive grease.

FIG. 5 is a schematic diagram of an electronic device in which the lens module according to an embodiment of the present disclosure may be employed; and

FIG. 6 is a flow diagram of a method for driving an actuator comprising a movable unit and a fixed unit according to an embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

The following describes embodiments of the present application with reference to the accompanying drawings. A person skilled in the art would understand that the present disclosure is not limited to the specific embodiments described below.

Camera modules typically comprises one or more lens groups movable for focusing or zooming purposes. Focusing is achieved by moving a lens group to change its distance to an image sensor. Zooming is achieved by changing a focal length of a lens group by moving one or more lenses in the lens group relative to one or more other lenses. Moving of a lens or a lens group is generally achieved by an actuator.

The moving-coil design is advantageous in that the weight of the movable unit may be reduced because typically coils are less weighty than magnets. On the other hand, the moving-coil design requires some mechanism to supply electric current to the movable unit.

Embodiments in which current is supplied via a leaf spring may not be suitable for a long stroke. Embodiments in which current is supplied via FPC (flexible printed circuit) may result in (i) a large size of a camera module in order to provide space to accommodate folded FPC; (ii) loss of a driving force of the actuator (that is, lower efficiency) due to reaction forces of the FPC; and (iii) increased complexity in assembling (that is, reduced assemblability) .

One embodiment of the present disclosure provides a lens module comprising a movable unit and a fixed unit of an actuator. The actuator is configured to drive the movable unit by an interaction (e.g., an electromagnetic interaction) , caused by supplying a current to the movable unit (e.g., a coil provided on the movable unit) , between the movable unit and the fixed unit. A conductive member (e.g., a conductive plate) provided on the movable unit is movably in contact with a conductive member (e.g., a guide shaft or a conductive pattern) fixed in position to the fixed unit for receiving a supply of current.

More generally, the present disclosure provides a component comprising a mechanism for supplying a current from a fixed unit to a movable unit. A conductive member provided on the movable unit is movably in contact with a conductive member fixed in position to the fixed unit for receiving a supply of current.

The present disclosure may also provide a method for driving an actuator comprising a movable unit and a fixed unit, wherein a conductive member provided on the movable unit is movably in contact with a conductive member fixed in position to the fixed unit, the method comprising: supplying a current, from a current supply electrically coupled to the fixed unit, to the conductive member fixed in position to the fixed unit; conveying the current, from the conductive member fixed in position to the fixed unit, via movable contact, to a conductive member provided on the movable unit; and driving the movable unit by an interaction (e.g., electromagnetic interaction) , caused by supplying a current to the movable unit (e.g., a coil provided on the movable unit) , between the movable unit and the fixed unit (e.g., a magnet provided on the fixed unit) .

Since the conductive member provided on the movable unit is movably in contact with the conductive member fixed in position to the fixed unit for receiving a supply of current, FPC is not necessary for supplying current. This eliminates the need of space for accommodating folded FPC, and thus allows a smaller size of the lens module. Moreover, since loss of driving force by reaction force of FPC is not incurred, its efficiency is not lost. Furthermore, since this does not rely on a leaf spring, a long stroke is allowed.

FIRST EMBODIMENT

FIG. 1A is a schematic diagram for illustrating a lens module according to a first embodiment of the present disclosure.

The lens module illustrated in FIG. 1A comprises a movable unit (comprising a lens 101, a lens frame 102, and a holder 103) and a fixed unit of an actuator. (It should be noted that the actuator may comprise one or more other units than illustrated. ) The actuator is configured to drive the movable unit by an interaction (e.g., an electromagnetic interaction) , caused by supplying a current to the movable unit (e.g., a coil 104 provided on the movable unit) , between the movable unit and the fixed unit (e.g., a magnet provided on the fixed unit) . The movable unit is guided by a first guide shaft 105 and a second guide shaft 106 to allow movement in a direction along the guide shafts. Although the number of guide shafts is not limited to two, providing at least two guide shafts is desirable for guiding linear movement.

In the illustrated embodiment, the coil 104 is provided around the first guide shaft 105, but this is not limiting. In the case of the coil 104 as illustrated, a permanent magnet shaped like a semi-cylinder may be provided on the fixed unit. The semi-cylindrical magnet may be placed such that the inner surface of the semi-cylinder faces the outer surface of the cylindrical outer shape of the coil. The inner surface of the semi-cylindrical magnet may have one polarity (e.g., S-pole or N-pole) , while the outer surface of the semi-cylindrical magnet may have the opposite polarity. The magnetic pole formed on the inner surface of the semi-cylindrical magnet interacts with magnetic pole (s) induced at one or both ends of the coil 104. It should be noted that the shape and arrangements of the coil and the magnet are not limited to this. Other shapes and other arrangements are also possible. For example, one or more circular coils may be provided on the movable unit. In some embodiments, a yoke may be provided with a magnet to enhance the electromagnetic interaction.

The lens frame 102 holds a lens or a lens group 101. The lens frame 102 is mounted on a holder 103. While the illustrated embodiment has separate lens frame 102 and holder 103, the lens frame 102 and the holder 103 may be an integrated component. Providing separate lens frame 102 and holder 103 is convenient for adjusting shift and tilt of the lens or the lens group.

In the illustrated example, the holder 103 has a first opening in which the first guide shaft 105 is inserted and a second opening in which the second guide shaft 106 is inserted.

In order to supply electric current to the movable unit, a conductive member provided on the movable unit is movably in contact with a conductive member fixed in position to the fixed unit. In the first embodiment, the conductive member provided on the movable unit comprises a first conductive plate 109 and a second conductive plate 110. The conductive member fixed in position to the fixed unit comprises the first guide shaft 105 that can be coupled to an electrode of a first polarity of a current supply and the second guide shaft 106 that can be coupled to an electrode of a second polarity of the current supply. In this embodiment, the first and second guide shafts are made of a conductive material (such as a metal) . The first conductive plate 109 and the second conductive plate 110 may be provided on the holder 103 by insert molding. The conductive member fixed in position to the fixed unit may or may not be directly attached to the fixed unit of the actuator.

According to this embodiment, the guide shafts used for guiding a linear movement of the movable unit are also used for supplying electric current to the movable unit. Since many lens modules comprise such guide shafts, this saves the number of parts used for current supply, and allows reduction in size.

To allow smooth movement of the movable unit along the guide shafts while maintaining electric contact, the first conductive plate 109 is movably in contact with the first guide shaft 105 via first bearing 107 made of a conductive material (e.g., a metal) , and the second conductive plate 110 is movably in contact with the second guide shaft 106 via second bearing 108 made of a conductive material. The conductive plates being movably in contact with the guide shafts via bearing provide an advantageous embodiment of the movable contact. In some embodiments, the first bearing 107 and the second bearing 108 have an opening in which a guide shaft is inserted. An inner diameter of the first bearing 107 substantially matches an outer diameter of the first guide shaft 105; and an inner diameter of the second bearing 108 substantially matches an outer diameter of the second guide shaft 106.

In some embodiments, a first end of the coil 104 is coupled to the first conductive plate 109 (e.g., by means of soldering) , and a second end of the coil 104 is coupled to the second conductive plate 110 (e.g., by means of soldering) . A current path is formed from one electrode of a current supply through the first guide shaft 105, the first bearing 107, the first conductive plate 109, the coil 104, the second conductive plate 110, the second bearing 108, and the second guide shaft 106 to the other electrode of the current supply. FIG. 1B illustrates the first and

second guide shafts

105, 106, the first and

second bearings

107, 108, and the first and second

conductive plates

109, 110.

When the first guide shaft 105 and the second guide shaft 106 are connected to the positive and negative electrodes (or negative and positive electrodes) of the current supply, respectively, by any of known means, an electric current flows through the coil, which causes an electromagnetic interaction between the coil and the magnet. This allows the holder to be driven in a direction of the guide shaft (i.e., a direction of the optical axis) . The sense of movement of the holder can be controlled by switching the polarity of the current supply.

In some embodiments, a gap between the first bearing 107 and the first guide shaft 105 and/or a gap between the second bearing 108 and the second guide shaft 106 are filled with a conductive grease.

Use of a conductive grease makes more reliable electric current conduction between the bearing and the guide shaft. In products which use bearing and a guide shaft, a small gap (clearance) will be typically provided between an inner surface of the bearing and an outer surface of the guide shaft to allow smooth sliding. Moreover, the bearing and the guide shaft would have some roughness on their surface due to machining. These factors may somewhat limit actual contact between the bearing and the guide shaft, which may be undesirable when such bearing and a guide shaft are used for electric conduction. Furthermore, when the movable unit is driven for operations such as focusing or zooming in a lens module, the state of contact will change continually because of varying camera posture and driving force from the actuator. This causes a problem in terms of securing electric conduction between the bearing and the guide shaft. A conductive grease is applied between the bearing and the guide shaft to address this problem. The conductive grease filling the small gap between the bearing and the guide shaft allows electric conduction even where the bearing and the guide shaft are not directly in contact.

FIG. 4A and FIG. 4B illustrate application of a conductive grease in a small gap present at a movable contact between the guide shaft and the bearing. The gap may be present due to surface roughness of those components as well as intentionally provided small clearance. The bearing is coupled to the conductive plate, which in turn is provided on the holder (e.g., by insert molding) .

The conductive grease has an additional advantage in its lubricating effect, which improves slidability between the bearing and the guide shaft.

While a conductive grease per se is known, it is conventionally used for discharging static electricity or preventing mechanical wear. The inventors of the present application realized that such a conductive grease may be used in the context of supplying current to improve electric conduction at the movable contact.

SECOND EMBODIMENT

FIG. 2A and FIG. 2B provide a schematic diagram for illustrating a lens module according to a second embodiment of the present disclosure.

The lens module illustrated in FIG. 2A and FIG. 2B comprises a movable unit (comprising a lens 201, a lens frame 202, and a holder 203) and a fixed unit of an actuator. (It should be noted that the actuator may comprise one or more other units than illustrated. ) The actuator is configured to drive the movable unit by an interaction (e.g., an electromagnetic interaction) , caused by supplying a current to the movable unit (e.g., a coil 204 provided on the movable unit) , between the movable unit and the fixed unit (e.g., a magnet provided on the fixed unit) . The movable unit is guided by a first guide shaft (comprising a first portion 205 and a second portion 206) and a second guide shaft 207 to allow movement in a direction along the guide shafts. Although the number of guide shafts is not limited to two, providing at least two guide shafts is desirable for guiding linear movement.

The coil 204 and the magnet may be similar to those of the first embodiment described above. While details are not repeated here for simplicity's sake, it should be noted that the shape and arrangement of the coil 204 is not limited to the illustrated example.

The lens frame 202 holds a lens or a lens group 201. The lens frame 202 is mounted on a holder 203. While the illustrated embodiment has separate lens frame 202 and holder 203, the lens frame 202 and the holder 203 may be an integrated component. Providing separate lens frame 202 and holder 203 is convenient for adjusting shift and tilt of the lens or the lens group.

In the illustrated example, the holder 203 has a first opening in which the first guide shaft is inserted and a second opening in which the second guide shaft is inserted.

Unlike the first embodiment, the second guide shaft 207 is not essential for supplying electric current to the movable unit in the second embodiment. Instead, the first guide shaft comprises a first portion 205 and a second portion 206, which are mechanically coupled via a non-conductive joint 212 (shown in FIG. 2C) .

In order to supply electric current to the movable unit, a conductive member provided on the movable unit is movably in contact with a conductive member fixed in position to the fixed unit. In the second embodiment, the conductive member provided on the movable unit comprises a first conductive plate 210 and a second conductive plate 211. (The latter is shown in the rear view in FIG. 2B. ) The conductive member fixed in position to the fixed unit comprises the first portion 205 of the first guide shaft that can be coupled to an electrode of a first polarity of a current supply and the second portion 206 of the first guide shaft that can be coupled to an electrode of a second polarity of the current supply. In this embodiment, the first portion 205 and second portion 206 of the first guide shaft are made of a conductive material (such as a metal) . The first conductive plate 210 and the second conductive plate 211 may be provided on the holder 203 by insert molding. The conductive member fixed in position to the fixed unit may or may not be directly fixed to the fixed unit of the actuator.

According to this embodiment, the first guide shaft used for guiding a linear movement of the movable unit is also used for supplying electric current to the movable unit. Since many lens modules comprise such guide shafts, this saves the number of parts used for current supply, and allows reduction in size. Moreover, when compared with the first embodiment, components for current supply are arranged around one of the two guide shafts, which allows further reduction in size and simplification in the actuator.

To allow smooth movement of the movable unit along the guide shafts while maintaining electric contact, the first conductive plate 210 is movably in contact with the first portion 205 of the first guide shaft via first bearing 208 made of a conductive material (e.g., a metal) , and the second conductive plate 211 is movably in contact with the second portion 206 of the first guide shaft via second bearing 209 made of a conductive material. The conductive plates being movably in contact with the portions of the first guide shaft via bearing provide an advantageous embodiment of the movable contact. In some embodiments, the first bearing 208 and the second bearing 209 have an opening in which the first guide shaft is inserted. An inner diameter of the first bearing 208 substantially matches an outer diameter of the first guide shaft; and an inner diameter of the second bearing 209 substantially matches an outer diameter of the first guide shaft.

In some embodiments, a first end of the coil 204 is coupled to the first conductive plate 210 (e.g., by means of soldering) , and a second end of the coil 204 is coupled to the second conductive plate 211 (e.g., by means of soldering) . A current path is formed from one electrode of a current supply through the first portion 205 of the first guide shaft, the first bearing 208, the first conductive plate 210, the coil 204, the second conductive plate 211, the second bearing 209, and the second portion 206 of the first guide shaft to the other electrode of the current supply.

When the first portion 205 of the first guide shaft and the second portion 206 of the first guide shaft are connected to the current supply, an electric current flows through the coil, which causes an electromagnetic interaction between the coil and the magnet. This allows the holder to be driven in a direction of the guide shaft (i.e., a direction of the optical axis) . Further details are not repeated here for simplicity's sake.

In some embodiments, a gap between the first bearing 208 and the first portion 205 of the first guide shaft and/or a gap between the second bearing 209 and the second portion 206 of the first guide shaft are filled with a conductive grease.

More details about a conductive grease are described above, and are not repeated here for simplicity's sake.

THIRD EMBODIMENT

FIG. 3A and FIG. 3B provide a schematic diagram for illustrating a lens module according to a third embodiment of the present disclosure.

The lens module illustrated in FIG. 3A and FIG. 3B comprises a movable unit (comprising a lens 301, a lens frame 302, and a holder 303) and a fixed unit of an actuator. (It should be noted that the actuator may comprise one or more other units than illustrated. ) The actuator is configured to drive the movable unit by an interaction (e.g., an electromagnetic interaction) , caused by supplying a current to the movable unit (e.g., a coil 204 provided on the movable unit) , between the movable unit and the fixed unit (e.g., a magnet provided on the fixed unit) . The movable unit is guided by a first guide shaft 305 and a second guide shaft 306 to allow movement in a direction along the guide shafts. Although the number of guide shafts is not limited to two, providing at least two guide shafts is desirable for guiding linear movement.

The coil 304 and the magnet may be similar to those of the first embodiment described above. While details are not repeated here for simplicity's sake, it should be noted that the shape and arrangement of the coil 304 is not limited to the illustrated example.

The lens frame 302 holds a lens or a lens group 301. The lens frame 302 is mounted on a holder 303. While the illustrated embodiment has separate lens frame 302 and holder 303, the lens frame 302 and the holder 303 may be an integrated component. Providing separate lens frame 302 and holder 303 is convenient for adjusting shift and tilt of the lens or the lens group.

In the illustrated example, the holder 303 has a first opening in which the first guide shaft 305 is inserted and a second opening in which the second guide shaft 306 is inserted.

Unlike the first embodiment and the second embodiment, the first guide shaft 305 and the second guide shaft 306 are not essential for supplying electric current to the movable unit in the third embodiment. Instead, the conductive member fixed in position to the fixed unit comprises a first conductive pattern and a second conductive pattern provided on the fixed unit.

In order to supply electric current to the movable unit, a conductive member provided on the movable unit is movably in contact with a conductive member fixed in position to the fixed unit. In the third embodiment, the conductive member provided on the movable unit comprises a first conductive plate 307 and a second conductive plate 308. (The latter is shown in the rear view in FIG. 3B. ) The first conductive plate 307 can be coupled to an electrode of a first polarity of a current supply and the second conductive plate 308 can be coupled to an electrode of a second polarity of the current supply. The first conductive plate 307 and the second conductive plate 308 may be provided on the holder 303 by insert molding. The conductive member fixed in position to the fixed unit may or may not be directly fixed to the fixed unit of the actuator.

The conductive member fixed in position to the fixed unit comprises a first conductive pattern and a second conductive pattern. In FIG. 3A and FIG. 3B, the first conductive pattern and the second conductive pattern are shown to be provided on FPC 309. However, this is not limiting. The first conductive pattern and the second conductive pattern may be metal traces on a circuit board or any other member. Even when the first conductive pattern and the second conductive pattern are provided on FPC 309, the FPC 309 need not be bendable, and FPC 309 may be unbendably mounted on a fixed unit (e.g., mounted on a housing of the fixed unit of the actuator) . Therefore, as with the first embodiment and the second embodiment described above, the lens module of the third embodiment eliminates the need of space for accommodating folded FPC.

According to this embodiment, the conductive plates being movable while keeping in contact with conductive patterns provide an advantageous embodiment of the movable contact. Moreover, this embodiments eliminates the bearing of the first and second embodiments, which allows further simplification in the actuator.

In some embodiments, the end portion that is of the first conductive plate 307 and that is movably in contact with the first conductive pattern and/or the end portion that is of the second conductive plate 308 and that is movably in contact with the second conductive pattern are brush-shaped.

In some embodiments, a first end of the coil 304 is coupled to the first conductive plate 307 (e.g., by means of soldering) , and a second end of the coil 304 is coupled to the second conductive plate 308 (e.g., by means of soldering) . A current path is formed from one electrode of a current supply through the first conductive pattern, the first conductive plate 307, the coil 304, the second conductive plate 308, and the second conductive pattern to the other electrode of the current supply.

When the first conductive pattern and the second conductive pattern are connected to the current supply, an electric current flows through the coil, which causes an electromagnetic interaction between the coil and the magnet. This allows the holder to be driven in a direction of the guide shaft (i.e., a direction of the optical axis) . Further details are not repeated here for simplicity's sake.

FURTHER ASPECTS

The lens module according to any one of the embodiments as described above may be used in a camera module. The camera module may comprise the lens module and an image sensor. Light transmitted through the lens module may be detected by the image sensor and stored in a storage device.

An electric device, such as a smartphone or a mobile phone, comprising such a camera module may be provided. The lens module reduced in size according to the present disclosure may be advantageous for use in a portable electronic device such as a smartphone or a mobile phone. FIG. 5 illustrates a portable electronic device, for example, a smartphone, that incorporates any of the embodiments of the present disclosure.

Embodiments of the present disclosure may also provide a method 600 for driving an actuator as illustrated in FIG. 6. The actuator comprises a movable unit and a fixed unit, wherein a conductive member provided on the movable unit is movably in contact with a conductive member fixed in position to the fixed unit. In step 610, the method comprises supplying a current, from a current supply electrically coupled to the fixed unit, to the conductive member fixed in position to the fixed unit. In step 620, the method further comprises conveying the current, from the conductive member fixed in position to the fixed unit, via movable contact, to a conductive member provided on the movable unit. In step 630, the method further comprises driving the movable unit by an interaction (e.g., electromagnetic interaction) , caused by supplying a current to the movable unit (e.g., a coil provided on the movable unit) , between the movable unit and the fixed unit (e.g., a magnet provided on the fixed unit) . It should be noted that the method may have more steps or fewer steps than illustrated. Various features including those described for the lens modules in the above are also applicable for method embodiments. Details are not repeated here.

While various embodiments are described above and illustrated in the drawings, the present invention is not limited to the specific embodiment described or illustrated. Features described for one embodiment of the present disclosure may be combined in any suitable manner with features described for another embodiment of the present disclosure, unless such a combination is impossible or explicitly stated to be excluded. A skilled person may recognize other objectives or advantages than those described in the above.

The unit division disclosed in embodiments of the present application is not limiting, and embodiments may be configured with other divisions of components.

Where appropriate, some functions (e.g., controlling of movement of a lens or a lens group) may be implemented in a form of a computer program for causing a processor or a computing device to perform one or more functions. For example, various signal processing and control functions may be implemented as a computer program. The computer program may be embodied on a non-transitory computer-readable storage medium. The storage medium may be any medium that can store a computer program and may be a solid-state memory such as a USB drive, a flash drive, a read-only memory (ROM) , and a random-access memory (RAM) ; a magnetic storage medium such as a removable or non-removable hard disk; or an optical storage medium such as an optical disc.

The foregoing descriptions merely illustrate various embodiments of the present application, and are not intended to limit the scope of the invention. Any variation that would readily occur to a person skilled in the art in view of the present disclosure shall fall within the scope of this application.

Claims

A lens module comprising a movable unit and a fixed unit of an actuator,

wherein the actuator is configured to drive the movable unit by an interaction, caused by supplying a current to the movable unit, between the movable unit and the fixed unit,

wherein a conductive member provided on the movable unit is movably in contact with a conductive member fixed in position to the fixed unit for receiving a supply of current.
The lens module of Claim 1, wherein the conductive member provided on the movable unit is movably in contact via bearing with the conductive member fixed in position to the fixed unit for receiving a supply of current.
The lens module of Claim 2,

wherein the conductive member provided on the movable unit comprises a conductive plate;

wherein the conductive member fixed in position to the fixed unit comprises a conductive guide shaft that can be coupled to a current supply;

wherein the conductive guide shaft is configured to guide the movable unit to allow movement in a direction along the guide shaft.
The lens module of Claim 1,

wherein the conductive member provided on the movable unit comprises a first conductive plate and a second conductive plate;

wherein the conductive member fixed in position to the fixed unit comprises a first guide shaft that can be coupled to an electrode of a first polarity of a current supply and a second guide shaft that can be coupled to an electrode of a second polarity of the current supply;

wherein the first guide shaft and the second guide shaft are configured to guide the movable unit to allow movement in a direction along the guide shafts;

wherein the first conductive plate is movably in contact with the first guide shaft via first bearing made of a conductive material; and

wherein the second conductive plate is movably in contact with the second guide shaft via second bearing made of a conductive material.
The lens module of Claim 4,

wherein the interaction between the movable unit and the fixed unit is an electromagnetic interaction between a coil provided on the movable unit and a magnet provided on the fixed unit;

wherein a first end of the coil is coupled to the first conductive plate, and a second end of the coil is coupled to the second conductive plate; and

wherein a current path is formed through the first guide shaft, the first bearing, the first conductive plate, the coil, the second conductive plate, the second bearing, and the second guide shaft.
The lens module of Claim 4,

wherein the movable unit comprises a holder;

wherein the first guide shaft is inserted in the first bearing provided inside a first opening of the holder, wherein an inner diameter of the first bearing substantially matches an outer diameter of the first guide shaft; and

wherein the second guide shaft is inserted in the second bearing provided inside a second opening of the holder, wherein an inner diameter of the second bearing substantially matches an outer diameter of the second guide shaft.
The lens module of Claim 6, wherein the first conductive plate and the second conductive plate are provided on the holder by insert molding.
The lens module of Claim 4, wherein a gap between the first bearing and the first guide shaft and/or a gap between the second bearing and the second guide shaft are filled with a conductive grease.
The lens module of Claim 1,

wherein the conductive member provided on the movable unit comprises a first conductive plate and a second conductive plate;

wherein the conductive member fixed in position to the fixed unit comprises a first portion and a second portion of a first guide shaft, wherein the first portion and the second portion of the first guide shaft are mechanically coupled via a non-conductive joint;

wherein the first guide shaft and a second guide shaft are configured to guide the movable unit to allow movement in a direction along the guide shafts;

wherein the first conductive plate is movably in contact with the first portion via first bearing made of a conductive material; and

wherein the second conductive plate is movably in contact with the second portion via second bearing made of a conductive material.
The lens module of Claim 9,

wherein the interaction between the movable unit and the fixed unit is an electromagnetic interaction between a coil provided on the movable unit and a magnet provided on the fixed unit;

wherein a first end of the coil is coupled to the first conductive plate, and a second end of the coil is coupled to the second conductive plate; and

wherein a current path is formed through the first portion of the first guide shaft, the first bearing, the first conductive plate, the coil, the second conductive plate, the second bearing, and the second portion of the first guide shaft.
The lens module of Claim 9,

wherein the movable unit comprises a holder;

wherein the first guide shaft is inserted in the first bearing provided inside a first opening of the holder and the second bearing provided inside a second opening of the holder, wherein an inner diameter of the first bearing and an inner diameter of the second bearing substantially match an outer diameter of the first guide shaft.
The lens module of Claim 11, wherein the first conductive plate and the second conductive plate are provided on the holder by insert molding.
The lens module of Claim 9, wherein a gap between the first bearing and the first portion of the first guide shaft and/or a gap between the second bearing and the second portion of the first guide shaft are filled with a conductive grease.
The lens module of Claim 1,

wherein the conductive member provided on the movable unit comprises a first conductive plate and a second conductive plate;

wherein the conductive member fixed in position to the fixed unit comprises a first conductive pattern and a second conductive pattern provided on the fixed unit,

wherein the first conductive plate is movably in contact with the first conductive pattern; and

wherein the second conductive plate is movably in contact with the second conductive pattern.
The lens module of Claim 14,

wherein the interaction between the movable unit and the fixed unit is an electromagnetic interaction between a coil provided on the movable unit and a magnet provided on the fixed unit;

wherein a first end of the coil is coupled to the first conductive plate, and a second end of the coil is coupled to the second conductive plate; and

wherein a current path is formed through the first conductive pattern, the first conductive plate, the coil, the second conductive plate, and the second conductive pattern.
The lens module of Claim 14, wherein the first conductive pattern and the second conductive pattern are provided in a FPC (flexible printed circuit) substantially unbendably attached to the fixed unit.
The lens module of Claim 14, wherein the end portion that is of the first conductive plate and that is movably in contact with the first conductive pattern and/or the end portion that is of the second conductive plate and that is movably in contact with the second conductive pattern are brush-shaped.
The lens module of Claim 14,

wherein the movable unit comprises a holder, wherein the first conductive plate and the second conductive plate are provided on the holder by insert molding.
The lens module of Claim 14, wherein one or more guide shafts provided fixed in position to the fixed unit are configured to guide the movable unit to allow movement in a direction along the one or more guide shafts.
The lens module of any one of Claims 1-19, wherein the movable unit comprises a lens group comprising one or more lenses and a lens frame that holds the lens group, wherein the movable unit is driven in a direction parallel to an optical axis of the lens group.
The lens module of any one of Claims 6, 7, 11, 12, and 18, wherein the movable unit comprises a lens group comprising one or more lenses and a lens frame that holds the lens group, wherein the movable unit is driven in a direction parallel to an optical axis of the lens group, and wherein the lens frame is integral with the holder.
A camera module comprising the lens module of Claim 20 and an image sensor.
An electronic device comprising the camera module of Claim 22.
The electronic device of Claim 23, which is a smartphone or a mobile phone.
A method for driving an actuator comprising a movable unit and a fixed unit, wherein a conductive member provided on the movable unit is movably in contact with a conductive member fixed in position to the fixed unit, the method comprising:

supplying a current, from a current supply electrically coupled to the fixed unit, to the conductive member fixed in position to the fixed unit;

conveying the current, from the conductive member fixed in position to the fixed unit, via movable contact, to a conductive member provided on the movable unit; and

driving the movable unit by an interaction, caused by supplying a current to the movable unit, between the movable unit and the fixed unit.
The method of Claim 25, wherein the interaction between the movable unit and the fixed unit is an electromagnetic interaction between a coil provided on the movable unit and a magnet provided on the fixed unit.
A component comprising a mechanism for supplying a current from a fixed unit to a movable unit,

wherein a conductive member provided on the movable unit is movably in contact with a conductive member fixed in position to the fixed unit for receiving a supply of current.