(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2008/0174187 A1
`Erixon et al.
`(43) Pub. Date:
`Jul. 24, 2008
`
`US 2008O174187A1
`
`(54) VIBRATOR TUBE
`
`(30)
`
`Foreign Application Priority Data
`
`(75) Inventors:
`
`Mats Erixon, Bjarred (SE); Mats
`Wolf, Sodra Sandby (SE); Stefan
`Hellstrom, Lund (SE)
`Correspondence Address:
`HARRITY SNYDER, L.L.P.
`11350 RANDOM HILLS ROAD, SUITE 600
`FAIRFAX, VA 22030
`
`(73) Assignee:
`
`SONY ERCSSON MOBILE
`COMMUNICATIONSAB, Lund
`SE
`
`(21) Appl. No.:
`
`11/909,199
`
`Mar. 15, 2006
`PCT/EP2006/OO2364
`
`(22) PCT Filed:
`(86). PCT No.:
`371
`1
`Seb. 20, 2007
`S. ),
`ep. AU,
`(2), (4) Date:
`O
`O
`Related U.S. Application Data
`(60) Provisional application No. 60/666,234, filed on Mar.
`29, 2005.
`
`Mar. 21, 2005 (EP) .................................. O5OO611O.O
`
`Publication Classification
`
`(51) Int. Cl.
`HO2K 33/6
`
`(2006.01)
`
`(52) U.S. Cl. ........................................ 310/15; 455/550.1
`
`ABSTRACT
`
`57
`(57)
`An el
`gnetic vib
`f
`in a portabl
`electromagnet1C V1 bratOr Or use 1n a Ortable COmmun1
`cation device (90) comprising a housing (20,30,40.50,60.70,
`80) comprising a track directed in a first dimension, a coiling
`2282
`prising at 1
`il
`iented i
`d
`s
`comprising at least one coil turn, oriented 1n a Secon
`dimension essentially perpendicular to the first dimension,
`coiled around the track and being arranged to receive an
`electric Voltage, a permanent magnet assembly (26.32.34.42.
`52.62.72.84) arranged for motion along the track to which
`said permanent magnet assembly is tightly fitted, and a fer
`rofluid mixture placed between the track and the permanent
`magnet assembly (26.32,3442.52.62.72.84), allowing
`motion of the permanent magnet assembly (26.32.34,42,52.
`62.72.84) in the first dimension independence of the electric
`Voltage as Supplied to the coiling (22.82).
`
`
`
`Exhibit 1009 - Page 1 of 9
`
`

`

`Patent Application Publication
`
`Jul. 24, 2008 Sheet 1 of 2
`
`US 2008/O174187 A1
`
`
`
`FIG. 3
`
`Exhibit 1009 - Page 2 of 9
`
`

`

`Patent Application Publication
`
`Jul. 24, 2008 Sheet 2 of 2
`
`US 2008/0174187 A1
`
`54 58
`
`
`
`xy.
`
`59 50 55 52
`
`
`
`
`
`FIG. 5 56
`
`Exhibit 1009 - Page 3 of 9
`
`

`

`US 2008/01 74187 A1
`
`Jul. 24, 2008
`
`VIBRATOR TUBE
`
`0001. The present invention relates to providing tactile
`stimuli to a user of a portable communication device.
`
`DESCRIPTION OF RELATED ART
`
`0002 Vibrators within small communication devices are
`most commonly designed as direct current (DC) motors
`where a counter weight is mounted off-center on the rotating
`axis. Upon rotation of the axis, the counter weight causes the
`vibrator to vibrate as a function of the rotational frequency.
`0003. There is also another type of vibrators, linear motor
`type vibrators, which comprise a magnet and a coil system
`that are driven by an alternating current (AC) electric source.
`Linear motor type vibrators typically have a metal spring
`attached to a top or a bottom of a housing in order to provide
`Support to the magnet system. One example of Such a linear
`vibrator is described in JP2004-1743.09.
`0004. Until today the best performance has been achieved
`by the DC-motor type vibrators. However, there are disad
`Vantages with this type of vibrators. The first disadvantage is
`that the response time is too long to enable a quick vibration
`response required in, for example, gaming. A second disad
`Vantage is that the counterweight is not protected against dust
`and mechanical damage to the same degree as the interior of
`the motor itself.
`0005. A drawback of the linear motor type vibrator is that
`the efficiency in terms of vibration is only about 25-50% of
`that of a DC-motor type vibrator.
`0006. The american patent document U.S. Pat. No. 6,768,
`230 discloses a device for electrical generation comprising
`multiple magnets in polar opposition to each other, arranged
`horizontally respecting a very critical angle of displacement,
`to induce an electrical signal in one or more Surrounding
`coils. Moreover a lubricant, preferably being a ferrofluid, that
`establishes a static coefficient of friction less than about 0.02.
`This document hence describes a horizontally restricted elec
`trical generation device, a narrow application, wherein a fer
`rofluid is being used.
`0007. There is hence still a need to overcome the deficien
`cies of the vibrators as presented above, to achieve an efficient
`vibrator, having a short response time without comprising any
`mechanical parts that can be damaged from outside influ
`CCCS.
`
`SUMMARY OF THE INVENTION
`
`0008. The invention is directed towards solving the prob
`lem of overcoming slow and inefficient provision of tactile
`stimuli to a user of a portable communication device.
`0009. This is achieved by providing quick and efficient
`vibrations of a portable communication device.
`0010. A first object of the present invention is to provide a
`device for providing quick and efficient vibrations of a por
`table communication device.
`0011. According to one aspect of this invention, this object
`is achieved by an electromagnetic vibrator for use in a por
`table communication device comprising:
`0012 a housing comprising a track directed in a first
`dimension,
`0013 a coiling comprising at least one coil turn, ori
`ented in a second dimension essentially perpendicular to
`
`the first dimension, coiled around the track and being
`arranged to receive an electric Voltage,
`0014 a permanent magnet assembly arranged for
`motion along the track to which said permanent magnet
`assembly is tightly fitted, and
`0.015 a ferrofluid mixture placed between the track and
`the permanent magnet assembly,
`0016 allowing motion of the permanent magnet assem
`bly in the first dimension in dependence of the electric
`Voltage as Supplied to the coiling.
`0017. A second aspect of the present invention is directed
`towards an electromagnetic vibrator including the features of
`the first aspect, wherein the ferrofluid is a low friction ferrof
`luid mixture comprising magnetic or magnetizable nano par
`ticles, and a carrier fluid, in which the magnetic or magnetiz
`able nano particles are dispersed.
`0018. A third aspect of the present invention is directed
`towards an electromagnetic vibrator including the features of
`the second aspect, wherein the nano particles comprise ferrite
`particles and the carrier fluid comprises an organic carrier
`fluid.
`0019. A fourth aspect of the present invention is directed
`towards an electromagnetic vibrator including the features of
`the first aspect, wherein the track comprises a tubular cavity
`directed in the first dimension and in which tubular cavity the
`first permanent magnet assembly is arranged to move.
`0020. A fifth aspect of the present invention is directed
`towards an electromagnetic vibrator including the features of
`the fourth aspect, wherein the tubular cavity has a circular
`cross section.
`0021. A sixth aspect of the present invention is directed
`towards an electromagnetic vibrator including the features of
`the fourth aspect, wherein the tubular cavity is linear in shape.
`0022. A seventh aspect of the present invention is directed
`towards an electromagnetic vibrator including the features of
`the fifth aspect, wherein the vibrator comprises at least a first
`centering element located on a first side of the permanent
`magnet assembly along the first dimension, for exerting an
`alternating attracting and repelling force directed in the first
`dimension on the permanent magnet assembly.
`0023. An eighth aspect of the present invention is directed
`towards an electromagnetic vibrator including the features of
`the seventh aspect, wherein the vibrator comprises a second
`centering element located on a second side of the permanent
`magnet assembly along the first dimensions for exerting a
`centering force directed in the first dimension on the perma
`nent magnet assembly.
`0024. A ninth aspect of the present invention is directed
`towards an electromagnetic vibrator including the features of
`the seventh aspect, wherein the first centering element com
`prises a first spring of which a first end is attached to a first end
`of the permanent magnet assembly, and of which a second
`end is attached to an inner side of a first end stop of the tubular
`cavity.
`0025 A tenth aspect of the present invention is directed
`towards an electromagnetic vibrator including the features of
`the eighth aspect, wherein the first and second centering
`elements comprise a first and a second spring, respectively,
`attached on either side of the permanent magnet assembly, for
`exerting centering forces directed in the first dimension on the
`permanent magnet assembly.
`0026. An eleventh aspect of the present invention is
`directed towards an electromagnetic vibrator including the
`
`Exhibit 1009 - Page 4 of 9
`
`

`

`US 2008/01 74187 A1
`
`Jul. 24, 2008
`
`features of the ninth aspect, wherein the first and second
`springs are non-linear in the first dimension.
`0027. A twelfth aspect of the present invention is directed
`towards an electromagnetic vibrator including the features of
`the eighth aspect, wherein the first and second centering
`elements comprise a second and a third permanent magnet,
`respectively, oriented in opposite direction in relation to one
`another in the first dimension, for exerting centering forces
`directed in the first dimension on the permanent magnet
`assembly.
`0028. A thirteenth aspect of the present invention is
`directed towards an electromagnetic vibrator including the
`features of the eighth aspect, wherein the first and second
`centering elements each comprise an essentially gas tight
`compartment and wherein there is an essentially gas tight fit
`at the contact surface between the permanent magnet assem
`bly and the surface wall of the tubular cavity.
`0029. A fourteenth aspect of the present invention is
`directed towards an electromagnetic vibrator including the
`features of the first aspect, wherein the coiling is arranged to
`receive an alternating current electric Voltage.
`0030. A fifteenth aspect of the present invention is directed
`towards an electromagnetic vibrator including the features of
`the first aspect, wherein the tubular cavity has a toroidal
`shape.
`0031. A sixteenth aspect of the present invention is
`directed towards an electromagnetic vibrator including the
`features of the fifteenth aspect, wherein the coiling is
`arranged to receive a direct current electric Voltage.
`0032. A second object of the present invention is to pro
`vide a portable communication device providing quick and
`efficient vibrations to its user.
`0033. A seventeenth aspect of the present invention is to
`provide a portable communication device comprising an elec
`tromagnetic vibrator comprising:
`0034 a housing comprising a track directed in a first
`dimension,
`0035 a coiling comprising at least one coil turn, ori
`ented in a second dimension essentially perpendicular to
`the first dimension, around the track and being arranged
`to receive an electric Voltage,
`0036 a permanent magnet assembly arranged for
`motion along the track, and
`0037 a ferrofluid mixture placed between the track and
`the permanent magnet assembly,
`allowing motion of the permanent magnet assembly in the
`first dimension in dependence of the electric Voltage as Sup
`plied to the coiling, and wherein the portable communication
`device is a mobile phone.
`0038. The present invention has thus the following overall
`advantages:
`0039 Firstly, the electromagnetic vibrator is more effi
`cient due to the application of a ferrofluid mixture subjected
`to a magnetic field.
`0040 Secondly, the electromagnetic vibrator also
`achieves a shorter response time as the friction between the
`magnet assembly and the housing or track, is minimized.
`0041. Thirdly, the electromagnetic vibrator is also void of
`any mechanical parts that can be damaged from outside influ
`CCCS.
`0042. It should be emphasized that the term “comprises/
`comprising when used in this specification is taken to
`specify the presence of stated features, integers, steps or
`
`components, but does not preclude the presence or addition of
`one or more other features, integers, steps, components or
`groups thereof.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`0043. The present invention will now be described in more
`detail in relation to the enclosed drawings, in which:
`0044 FIG. 1 schematically shows a housing-coil system,
`0045 FIG. 2 schematically shows housing-coil-magnet
`system according to one embodiment of the present inven
`tion,
`0046 FIG. 3 schematically shows a more detailed hous
`ing-magnet arrangement according to one embodiment of the
`present invention,
`0047 FIG. 4 schematically shows a housing-magnet
`arrangement according to one embodiment of the present
`invention,
`0048 FIG. 5 schematically shows a housing-magnet
`arrangement according to one embodiment of the present
`invention,
`0049 FIG. 6 schematically shows a housing-magnet
`arrangement according to one embodiment of the present
`invention,
`0050 FIG. 7 schematically shows a housing-magnet
`arrangement according to one embodiment of the present
`invention,
`0051
`FIG. 8 schematically shows a housing-coil-magnet
`arrangement according to one embodiment of the present
`invention, and
`0.052 FIG.9 schematically shows a portable communica
`tion device according to one embodiment of the present
`invention.
`
`DETAILED DESCRIPTION OF THE
`EMBODIMENTS
`0053. The invention is directed towards solving the prob
`lem of overcoming slow and inefficient provision of tactile
`stimuli to a user of a portable communication device.
`0054 Electromagnetic vibrators utilizes the influence on a
`magnet by a magnetic field, which field generally is created
`by letting an electric current flow through a coiling. Depen
`dent on the design of Such magnet-coil system either a direct
`current (DC) electric Voltage or an alternating current (AC)
`electric Voltage is Supplied to the coil, enabling an AC electric
`current and a DC electric current to flow through the coil.
`0055 FIG. 1 schematically shows an elongated hollow
`housing 10 around which a coiling is wound. An electric
`Voltage is applied to the connections 14, creating a magnetic
`field 16 that is directed along the long axis of the housing. The
`direction of the magnetic field is dependent on the polarity of
`the applied electric Voltage.
`0056. As is shown in FIG. 2 a housing is designed to have
`a circular cross section, forming a hollow straight cylinder. A
`coiling 22 is would around the circularhousing, which coiling
`is Supplied with an electric Voltage over the connectors 24. A
`magnet 26 is positioned within the housing 20. On Supplying
`an electric Voltage over the coiling 22 at the connectors 24, a
`magnetic field is created within and around the coiling 22.
`The magnet 26 is preferably oriented so that the magnetic axis
`of the magnet is parallel with the symmetry axis of the cylin
`drical housing, and most preferably that the directions of the
`magnetic axis and the center of the magnetic field, created by
`the coiling, coincide.
`
`Exhibit 1009 - Page 5 of 9
`
`

`

`US 2008/01 74187 A1
`
`Jul. 24, 2008
`
`0057 The two magnetic fields, that is the magnetic field as
`created by the electric current flowing through the coiling and
`the one as formed by the magnet, interact with each other and
`create relative attracting or repelling forces, dependent on the
`relative position of the magnet and the coiling within the
`housing, and the current that is fed through the coiling.
`0058 According to one embodiment of the present inven
`tion, the housing has a linear shape, as shown in FIG. 2, which
`means that the magnet can be made to move back and fourth
`within the linear housing, by applying the electrical Voltage
`over the connectors 24 of the coiling.
`0059. According to one embodiment of the present inven
`tion the track is a tubular cavity. The cross section of the
`tubular cavity may also be circular. According to another
`embodiment of the present invention, it may also have any
`other shape Such as rectangular or triangular shape or a non
`polynomial shape Sucha horse-shoe shape or any other shape.
`0060 According to one embodiment the track is a rail that
`is protruding from a Surface within the housing. According to
`this embodiment the magnet or magnet assembly, as we shall
`see below, is fitted around or on the track Such that the magnet
`or magnet assembly is guided by the track along the housing
`upon influence of the magnetic field generated around the
`coiling.
`0061 Alternatively, the track may also be a trace that is
`recessing from the Surface within the housing, according to
`another embodiment of the present invention. Here, the mag
`net or magnet assembly may comprise a rail that is arranged
`to fit into the trace recessing from the housing surface. The
`housing Surface may not necessarily be an interior Surface
`located within the housing, but may very well be an exterior
`Surface of housing having a cross section that is non-closed.
`One example of such a shape is the horse-shoe shaped hous
`ing, as mentioned above.
`0062. With reference to FIG. 3, schematically showing a
`more detailed housing-magnet arrangement according to one
`embodiment of the present invention, the present invention is
`further explained.
`0063. The electromagnetic vibrator according to the
`present invention comprises the inclusion of a ferrofluid
`located in an interface between the magnet or magnet assem
`bly and a track along which the magnet can be made to move.
`0064. In FIG.3, the electromagnetic vibrator, as schemati
`cally disclosed, comprises a linear housing 30, a permanent
`magnet 32 and a magnet Support 34, 36. The magnet 32 and
`the magnet Support 34.36 togetherform the magnet assembly.
`0065 According to this embodiment of the present inven
`tion, the magnet assembly and the linear housing 30 are
`connected over a sliding surface interface 39. It is this inter
`face that comprises a ferrofluid according to a preferred
`embodiment of the present invention.
`0066. According to one embodiment of the present inven
`tion, the ferrofluid comprises magnetized or magnetizable
`nano particles that are dispersed in a carrier fluid. Such fer
`rofluids hence show magnetic properties despite of the fact
`that the ferrofluid is a fluid.
`0067. Upon positioning a ferrofluid within a magnetic
`field the fluid, experiences a force and travels in the direction
`of the magnetic field lines. Such a movement along the mag
`netic field lines results in a collection offerrofluid at positions
`where the density of magnetic field lines is high, that is where
`the magnetic field strength is high. As magnetic particles
`experience a force along the field lines, the particles are not
`moved across the magnetic field lines. If a Surface for this
`
`reason is crossed by magnetic field lines, a ferrofluid contain
`ing particles that are magnetic, experiences an attraction force
`from this Surface, or rather the magnetic field crossing the
`Surface.
`0068. In principle, a repulsion force could be experienced,
`but since the repulsion force alternative is energetically non
`favourable over the attraction alternative, the magnetic par
`ticles experience an attraction force.
`0069. Due to this attraction force the magnetic ferrofluid is
`collected on the surface. Since the ferrofluid travels along the
`magnetic field lines, an orientation of the magnetic field lines
`and the surface for which the magnetic field lines are parallel
`with the normal to the surface, that is perpendicular to the
`plane of the surface, is beneficial for maintaining the ferrof
`luid on the surface.
`0070. In case the normal of the surface would be perpen
`dicular to the magnetic field lines, the ferrofluid would not
`remain on the surface, but rather be attracted away in the
`direction of the field lines. This would hence result in a
`Surface without comprising any ferrofluid.
`0071. In practise, orientations for which the angle between
`the normal to the Surface and the magnetic field lines, is less
`than about n/4 rad (that is 45 degrees), lend the magnetic
`particles of the ferrofluid the attraction force, which makes
`the ferrofluid remain on the surface.
`(0072 Returning to FIG. 3, a few magnetic field lines 38
`are schematically indicated. At the sliding Surface interface
`39 between the magnet assembly and the housing 30, the
`magnetic field line is approximately parallel with the normal
`to the surface of the interface 39. This will thus be beneficial
`since the ferrofluid will remain on the surface and not travel
`away from the Surface.
`0073. According to one embodiment of the present inven
`tion, when applying a ferrofluid comprising magnetized par
`ticles on the interface surface between the housing and the
`magnet assembly, the friction between said housing Surface
`and the magnet assembly is very low, due to the properties of
`the ferrofluid when subjected to magnetic field lines crossing
`the surface interface.
`(0074) A very low friction in the interface between the
`magnet assembly and the housing means that the magnet
`assembly can move back and/or fourth along the housing with
`very little losses upon application of an electric field over the
`connectors 14, 24 of the coiling, as depicted in FIGS. 1 and 2.
`respectively.
`0075 According to one embodiment of the present inven
`tion, a very efficient electromagnetic vibrator is thus
`achieved.
`0076 For a linear vibrator the magnet assembly including
`the magnet is intended to move back and forth within the
`housing and inside the coiling. In order to move the magnet in
`one direction one polarity of the electric Voltage, that is
`applied to the coiling, is required, and in order to move the
`magnet in the opposite direction the reverse polarity of the
`electric Voltage is needed. If an alternating current electric
`Voltage is applied to the coiling the magnet assembly would
`thus move back and forth in one dimension as determined by
`the track or the housing, that is back in one direction and forth
`in the opposite direction. As Such an electric Voltage is applied
`the magnet assembly can be made to move back and forth
`without the assistance by any further elements or effects.
`0077. When an electromagnetic vibrator according to the
`present invention, is not in use, the magnet assembly would
`still experience a very low friction against the housing Sur
`
`Exhibit 1009 - Page 6 of 9
`
`

`

`US 2008/01 74187 A1
`
`Jul. 24, 2008
`
`face, which could make the magnet assembly to hit the top
`end or bottom end of the housing or tubular cavity, since the
`magnetic field from the magnet remains unchanged. Such a
`behaviour is disadvantageous since it would create mechani
`cal damage to the electromagnetic vibrator, at the same time
`as it could create an unpleasant tactile experience for a user of
`a portable communication device comprising the electromag
`netic vibrator. In addition, hitting a top end and/or bottom end
`would cause an un-desired noise.
`0078. As the motion direction of the magnet assembly is
`dependent on the polarity of the applied electrical Voltage, an
`applied polarity causing the magnet assembly to move away
`from the center of the coiling, is un-wanted in case the magnet
`assembly already is positioned near or at either one of the top
`end or bottom end of the housing. If Such an electric Voltage
`is applied to the coiling when the magnet assembly is posi
`tioned near or at the end of the housing, the magnet assembly
`could again hit the bottom end or top end of the housing,
`creating the problems as described in the paragraphs above.
`0079. In order to avoid hitting the top or bottom end of the
`housing by the magnet assembly, one or two centering ele
`ments are introduced in the housing, for centering the magnet
`assembly in the axial direction of the housing.
`0080. By referring to FIGS. 4–7, schematically showing
`housing-magnet arrangements, different embodiments of the
`present invention are explained, by focusing on the centering
`elements comprised in the respective housing.
`0081
`FIG. 4 discloses one embodiment in which the elec
`tromagnetic vibrator comprises a housing 40, a magnet 42, a
`right hand side end stop 48 and a compartment 44 that is
`formed between the magnet 42 and the right hand side end
`stop 48. On the left side of the magnet 42 in the interior of the
`housing a second compartment is also formed between the
`magnet and a left hand side end stop, (not denoted in FIG. 4).
`0082 In the compartment 44 on the right side of the mag
`net 42, a centering element 46 is schematically shown.
`According to this embodiment of the present invention, the
`centering element is a spring, of which one end is attached to
`the magnet and of which the other end is attached to the
`interior side of the right hand side end stop 48. The spring,
`being one example of a centering element, has the function of
`centering the magnet within the housing to a position essen
`tially in the center of the housing in the axial dimension.
`0083. The spring 46 has the advantage that it allows the
`back- and forth motion of the magnet or magnet assembly,
`since the spring according to this embodiment allows both an
`elongation upon pulling of the magnet, and a compression
`upon pushing of the magnet.
`0084. According to one embodiment of the present inven
`tion there is no requirement for the spring 46 to Support the
`magnet 42 or magnet assembly in a transverse or radial
`dimension of the housing/vibrator. The reason for this is that
`there is mechanical sliding contact in the interface 39 between
`the surface of the magnet assembly and the surface side of the
`housing 30. The magnet assembly is guided by the track
`which in FIG. 3 is shown as an interior cavity.
`0085. A non-linear spring can be characterized by having
`a forcefunction, rather thana force constant, as the ratio of an
`applied longitudinal force and the change in length of the
`spring. The usage of a non-linear spring allows a greater
`amplitude of the moving magnet in the axial dimension for a
`constant loss, maintaining the centering element functional
`
`I0086 According to one embodiment of the present inven
`tion, the centering element is a non-linear spring.
`I0087 FIG. 5 schematically shows another embodiment of
`the present invention, an electromagnetic vibrator comprising
`two centering elements 56, 57 wherein a first centering ele
`ment 56 is positioned in a first compartment 54 and a second
`centering element 57 is positioned in a second compartment
`55.
`I0088 According to one embodiment, the left side of the
`first spring 56 is attached to the right side of the magnet 52 or
`magnet assembly, and the right side of the spring 56 is
`attached to the left side of the right side end stop 58 of the
`housing 50 or the entire electromagnetic vibrator. Similarly
`the left side of the second spring 57 is attached to the right side
`of left side end stop 59, and the right side of the spring 57 is
`attached to the left side of the magnet 52 or magnet assembly.
`I0089 Analoguous to another embodiment that was
`described above, there is no requirement of the first and
`second springs 56, 57 to support the magnet in a transverse
`dimension, perpendicular to the axial dimension of the hous
`1ng
`0090. In addition, the first and second springs 56.57 may
`be designed to show a non-linear force function behaviour.
`This may for example be realized by using a non-constant
`pitch of the springs 56,57.
`0091. In FIG. 6 an electromagnetic vibrator according to
`another embodiment of the present invention is presented.
`Within this embodiment the centering elements each com
`prise a centering magnet 66.68 that is oriented to exert a
`repelling force on the moving magnet 62. On the right side the
`right compartment 64 is defined as the volume within the right
`side of the moving magnet 62 or magnet assembly, the hous
`ing 60, and the left side of the left centering magnet 66. The
`left compartment 65 is similarly defined as the volume com
`prised within the left side of the moving magnet 62, the
`housing 60 and the right side of the centering magnet 68. The
`right and left centering magnets are thus examples of right
`and left end stops of the housing 60.
`0092. Due to the repelling forces between the moving
`magnet 62 and the centerings magnets 66, 68, the moving
`magnet is hindered from hitting either one of the left or right
`end stops, which in this embodiment are comprised by the
`centerings elements of the electromagnetic vibrator.
`0093. The moving magnet 62 or magnet assembly within
`the above described embodiments in FIGS. 4,5 and 6, may be
`designed with axial channels penetrating through the moving
`magnet and or the Support structure, comprised in the magnet
`assembly, to allow a gas, for example air, to flow between the
`two compartments, minimizing the influence of the enclosed
`gas in the compartments on the motion of the magnet.
`(0094 FIG. 7, shows yet another embodiment of the elec
`tromagnetic vibrator according to the present invention, com
`prising a housing 70 and a right end stop 76 and a left end stop
`78 of the housing. According to this embodiment the housing
`and the right and left end stops are tightly fitted together
`forming a gas tight enclosure. In addition the magnet 72 or
`magnet assembly is also tightly fitted against the housing 70.
`The tight seal between the magnet assembly and the housing
`is realized by ferrofluid being applied in the interface between
`the magnet assembly and the housing (see FIG.3 wherein the
`interface is denoted with 39). Within this embodiment of the
`present invention, the left and right compartments are thus
`essentially gas tight.
`
`Exhibit 1009 - Page 7 of 9
`
`

`

`US 2008/01 74187 A1
`
`Jul. 24, 2008
`
`0095 Since gases are compressible, the gas tight compart
`ments filled with a gas receive a spring function, exerting a
`pushing force on the moving magnet assembly when being
`compressed, and a pulling force when being decompressed.
`By changing the gas pressure of the two compartments the
`forces exerted on the magnet assembly can easily be adjusted.
`0096. The centering elements in this embodiment are thus
`essentially gas tight compressible and decompressible com
`partments, having the beneficial property of comprising a
`limited number of parts.
`0097. According to an alternative embodiment of the
`present invention the tubular cavity onto which the moving
`magnet is tightly fitted comprises a toroid 80, as Schemati
`cally shown in FIG. 8. By winding a coiling 82 around the
`toroid 80 and applying a DC-electrical voltage over the con
`nectors 86 of the coiling 82, a magnet 84 within the tubular
`cavity, here the toroid, 80, experiences a uni-directed force 88
`moving the magnet in one circular dimension around the
`toroid.
`0098. In this embodiment, as in the other embodiments as
`presented above, it is beneficial to position the moving mag
`net within a supporting structure 34, 36 as shown in FIG.3, in
`order to orient the magnetic field lines with a substantial
`component directed parallel with the normal of the sliding
`Surface in the interface between the magnet assembly and the
`housing.
`0099. As the ferrofluid preferably is applied in the sliding
`Surface interface between the magnet assembly and the hous
`ing for all the embodiments, the electromagnetic device
`according to the present invention is given a high efficiency
`with only very minor losses when being used.
`0100. In addition, as the ferrofluid provides a very low
`friction within the orientation as described above, starting an
`electromagnetic vibrator by applying an electric Voltage over
`connectors connected to the coiling, is performed within a
`short time, that is the response time from an applied electric
`Voltage until experienced vibrations is very short.
`0101 Due to the design of the electromagnetic vibrators
`according to the various embodiments as described above, the
`interior of the vibrator is efficiently protected by the sur
`rounding housing, Such that damage on the moving parts due
`to outside influences is minimized.
`0102 FIG. 9 presents a portable communication device,
`comprising an electromagnetic vibrator according to one
`embodiment of the present invention. In this figure the por
`table communication device is designed as a mobile phone 90
`comprising the electromagnetic vibrator 92. This is only one
`example of a portable communication device, which may
`comprise any type of portable computer Such as a personal
`digital assistant, etc.
`0