FR2819367A1 - PORTABLE ELECTRIC APPARATUS HAVING SOUND RESTITUTION MEANS - Google Patents

Abstract

The portable electric appliance (10) comprises: - a chassis (12); - an audio source (24) adapted to generate a control signal representative of a sound sequence; and- sound reproduction means (20) comprising a loudspeaker (22) for transmitting sound connected to said audio source (24) for controlling it as a function of said control signal representative of a sound sequence. ) of sound reproduction comprise a source (28) of mechanical excitation mechanically coupled to said chassis (12) and connected to said audio source (24) for its control as a function of said control signal representative of a sound sequence. Application to a telephone mobile.

Description

The present invention relates to a portable electrical appliance of the type

  comprising: - a chassis; - an audio source adapted to generate a control signal representative of a sound sequence; and - sound reproduction means comprising a sound emission loudspeaker connected to said audio source for its control as a function of said signal

  representative of a sound sequence.

  This portable electrical device is for example a mobile telephone,

  a laptop or PDA.

  Mobile phones, as well as many other portable electrical devices, include sound reproduction means allowing the generation of acoustic waves in the audible frequency band.

by the man.

  These sound reproduction means include at least one loudspeaker.

  speaker with a membrane whose excitation allows the creation of

sounds in the environment.

  Due to the generally reduced dimensions of electrical appliances

  that portable, the speaker (s) used have a reduced diameter, this one

  cannot exceed a few centimeters.

  These speakers do not allow reproduction of frequencies.

  these basses correspond to the bass sounds. Indeed, the frequency of cou-

  a speaker’s pure bass is directly related to its diameter. In part-

  culier, the signals in the corresponding sub-bass band

  at frequencies from 20 Hz to 300 Hz cannot be reproduced by a loudspeaker

small diameter speaker.

  For the moment, there is no known solution making it possible to repro-

  reduce, in free field, the low and infra-low band in a modern telephone

  bile or a laptop with a small speaker.

  The impossibility of reproducing bass sounds with such portable electrical devices is particularly detrimental for the sound quality obtained, in particular for listening to contemporary music or sounds.

serious are very present.

  The object of the invention is to provide a solution to this problem by

  putting the perception of infra-low frequencies even with a device

  small portable electric.

  To this end, the invention relates to a portable electrical appliance, of the aforementioned type, characterized in that said means of sound reproduction

  include a source of mechanical excitation mechanically coupled to

  said chassis and connected to said audio source for its piloting in function

  of said control signal representative of a sound sequence.

  According to particular embodiments, the portable electrical appliance comprises one or more of the following characteristics: said source of mechanical excitation comprises a source of controlled force connected to said audio source and a movable assembly movable relative to said source of controlled force, said controlled force source being adapted to act on said moving element, said controlled force source and / or said moving element being fixed to said chassis;

  - said source of mechanical excitation is adapted for displacement-

  rectilinear ment of said moving assembly; - Said source of mechanical excitation forms a resonant system; - said mechanical excitation source includes a return member

  elastic of said moving assembly interposed between said source of force

  mandée and said moving equipment; - The resonance frequency of said resonant system is substantially equal to 100 Hz;

  - Said source of mechanical excitation comprises a damping member

  sement interposed between said source of controlled force and said moving equipment;

  - Said sound reproduction means include means for-

  servicing of said force source controlled according to a para-

  meter representative of the movement of said moving assembly; - Said sound reproduction means comprise a low-pass filter between said source of mechanical excitation and said audio source;

  - said sound reproduction means include a double integration

  between said source of mechanical excitation and said audio source; it includes means for securing said chassis to a resonant plate;

  - Said securing means comprise a suction cup fixed to-

  said chassis and adapted to be applied against said resonant plate; said chassis has an external gripping face of said portable electrical appliance, and said source of mechanical excitation is applied to said external gripping face; and

  - it is a device performing at least one of the main functions

  blades specific to the group of devices comprising: 10. a mobile telephone; a laptop; a portable electronic agenda;

a portable television.

  The invention will be better understood on reading the description which will

  follow, given only as an example and made with reference to the

sins, on which:

  - Figure 1 is a side view, schematic and in longitudinal section-

  nale of a mobile telephone according to the invention; FIG. 2 is a schematic view in longitudinal section of a mechanical excitation source integrated in the mobile telephone of FIG. 1; and

  - Figure 3 is a side view, schematic and in longitudinal section-

  nale of an alternative embodiment of the mobile telephone of FIG. 1, this

  the telephone being shown lying on a tray.

  In Figure 1 is shown a mobile phone 10 having a housing 12 having a front face 14 and a rear face 16. Face 16

  back of the mobile phone constitutes a solid wall essentially con-

  tinues. As is known per se, a keyboard 18 and a screen 19 are present on

the front face 14 of the telephone.

  In addition, the telephone includes means 20 for sound reproduction.

  These means include a diaphragm speaker 22 which is disposed inside the housing 12 in line with an orifice for the passage of sound waves formed through the front face 14 of the telephone. The loudspeaker 22 is of reduced size and does not allow the reproduction of frequencies below

300 Hz.

  The loudspeaker 22 is connected to an audio source 24 suitable for

  generate a control signal representative of a sound sequence.

  The audio source 24 is constituted, for example, by means of reception of the mobile telephone. These means are of any suitable type and do not

  will not be described in detail in the following description.

  The output of the audio source 24 is connected directly by a conduc-

  speaker 26 to loudspeaker 22 for control from the control signal

product.

  In addition and according to the invention, the means 20 for sound reproduction of the

  mobile telephone comprise a source 28 of controlled mechanical excitation.

  This source 28 is mechanically coupled to the chassis of the telephone, that is to say

  ie the carrying structure of the mobile phone. In the embodiment

  tion envisaged, the chassis of the telephone consists of the housing 12.

  More specifically, the source 28 of mechanical excitation is mechanically coupled to a rear face 16 of the mobile telephone in order to allow

  transmission of mechanical waves from the excitation source 28 to

  than on the rear face 16, in order to cause mechanical vibrations of this

face.

  The source 28 of mechanical excitation is connected to the audio source 24 through a signal conditioning chain 30. The chain 30 first comprises, at the output of the audio source 24, a low-pass filter 32

  whose cutoff frequency is substantially equal to 300 Hz.

  An amplifier 34 is connected at the output of the low-pass filter 32, the output of the amplifier 34 being directly connected to the source 28 of mechanical excitation. Advantageously, the source 28 of mechanical excitation forms a

  resonant system. An example of such a source is shown in the fi

gure 2.

  The source 28 includes a source 36 of controlled force connected in

  output from the signal conditioning chain 30. Source 28 of excitement

  mechanical tion further comprises a movable assembly 38 displaceable in translation relative to the source 36 of force controlled under the action of the latter. One of the source 36 of commanded force and the moving crew 38

  is rigidly attached to the rear face 16 of the housing. In the embodiment

  tion illustrated, the source of controlled force 36 is fixed to the rear face 16 of the housing and the movable assembly 38 is therefore movable relative to the face

16 rear of the housing.

  The source 36 of controlled force comprises an electromagnet 40 received in a casing 42. The casing 42 comprises fixing means on the rear face 16 of the housing, the source 28 of mechanical excitation being mounted inside the housing. A coil 44 of the electromagnet is fixedly mounted at

  inside the casing 42. The movable assembly 38 includes a magnet bar

  that 46 displaceable by sliding along the axis of the winding 44. The bar

  magnetic 46 passes through a wall of the casing 42.

  The moving element 38 further comprises a moving mass 48 fixed to

  the end of the magnetic bar 46 projecting from the casing 42.

  The source 28 of mechanical excitation is disposed in the mobile telephone, so that the movement of the mobile assembly 38 takes place in a direction substantially perpendicular to the main plane of the

rear 16.

  A damping element 49 formed for example by a block of foam is interposed between the source 36 of controlled force and the crew

  mobile 38. In the embodiment, the damping element is

  placed around the magnetic bar 46 between the casing 42 and the mass 48.

  In addition, an elastic return member, such as a spiral spring

  ensures the connection between the casing 42 and the movable assembly 38 formed of the bar-

  magnetic reel 46 and moving mass 38.

  The source 28 of mechanical excitation illustrated in FIG. 2 forms a resonant system. The resonance pulse is equal to k / m o k is the stiffness of the spring 50 and m is the mass of the moving element 38. The mass

  m is substantially equal to the mass of the mobile mass 48.

  For such a resonant system, the quality factor at resonance is

  function of the moving assembly 38, the spring 50 and the damping element 49

  ment. A damping element 49 producing a weak damping allows a significant generation of vibrations but whose spectrum is very

  tightened. A damping element 49 producing high damping

  vé allows to extend the vibration spectrum but reduces the amplitude of the vi-

  brations. Advantageously, the moving element 38 and the spring 50 are chosen so that the resonance frequency of the source 28 of mechanical excitation

is substantially equal to 100 Hz.

  The damping element 49 is chosen to produce a damping

  ment such that an attenuation of 20 dB for example is obtained at the frequency

quence of 200 Hz.

  The moving element 38, the commanded force source 36, the damping

  sor 49 and spring 50 are dimensioned so that the amplitude of the oscillations

  tions of the moving crew 38 is maximum in the frequency range

from 20 Hz to 300 Hz for example.

  As a variant, the spring 50 and / or the damping element 49 are

deleted.

  The source 36 of controlled force used in the source 28 of mechanical excitation is advantageously controlled by regulation means known per se. The servo parameter is preferably

  a parameter representative of the movement of the moving assembly 38. This pa-

  rameter is for example the speed of the moving assembly, its position, or its acceleration. During operation of the mobile telephone 10, the audio source 24 produces a control signal representative of a sound sequence. The control signal is applied, on the one hand, to the loudspeaker 22 and, on the other hand

  hand, at the entrance to the signal conditioning chain 30.

  The control signal supplied by the audio source 24 comes for example from a data file received by the mobile telephone 10, this file

  being for example in MP3, ATTRAC3 or WAV format.

  The control signal causes the membrane of the

  speaker 22 and the production of sound waves.

  Simultaneously, the same control signal is filtered by the low-pass filter 32 then is amplified by the amplifier 34. The signal thus conditioned then excites the electromagnet 40, which ensures a corresponding displacement.

of the moving crew 38.

  The movements of the movable assembly 38 relative to the casing 42, itself secured to the housing 12 cause on the housing, and in particular its rear face 16, a force which is proportional to the derivative of the signal

  ordered. This force is in fact directly proportional to the acceleration

  tion and mass of the moving part 38, according to the fundamental law of dynamics. When the user holds the housing 12 of the mobile phone in his hand, denoted M in FIG. 1, with the rear face 16 of the housing applied against the palm of his hand, the force produced by the source 28 of mechanical excitation is applied directly on the user's hand. This last

  then perceives the vibration produced by the source 28 of mechanical excitation.

  This mechanical vibration reproduces the frequencies of the sub-bass band

of the sound sequence.

  It is generally observed that the bass sounds including the frequency

  quence is included in the infra-low band are perceived as much by the body surface of the human being as by the eardrum of his ears. So,

  the mechanical stress applied on the palm of the hand allows the user to

  sator of the mobile phone to feel a vibration in the infrared band

  low, this vibration being perceived as a component of the signal so-

  nore whose higher frequencies are reproduced by the speaker 22.

  As a variant, in the source of mechanical excitation 28, the movable assembly 38, the spring 50 and the damping element 49 are formed by the same member, this member being constituted for example by an elastic blade coated with rubber. . The elastic blade then performs both the function

  of the moving mass and of the elastic return member, the rubber

  for its part the damping function.

  In Figure 3, there is shown an alternative embodiment of the tele-

mobile phone of figure 1.

  In this embodiment, the elements identical or analogous to those of the embodiment of FIG. 1 are designated by the same reference numbers. According to this alternative embodiment, the packaging chain 30

  signal signal comprises, between the low-pass filter 32 and the amplifier 34, a double

  ble integrator 60 allowing two successive integrations of the

  control signal with respect to time.

  Furthermore, a suction cup 62 is mechanically attached to the rear face 16 of the mobile telephone. This suction cup has an elastic cap

  63, the suction surface of which is turned away from the rear face 16.

  Advantageously, this suction cup 62 is fixed to the right of the source 28 of ex-

mechanical quote.

  The suction cup 62 ensures a fixing by suction of the tele-

  phone mobile against the surface of an elastically deformable plate 64.

  This plate is formed for example by the desk top or any

  another large tray.

  For its operation, the mobile phone rests with its face 16

  rear extending substantially parallel to the plate 64. In this position

  position, a damping cushion 66 is advantageously interposed between the housing 12 of the mobile phone and the plate 64 in order to avoid any contact

  rigid between the housing and the plate.

  During the operation of the mobile telephone, the control signal representative of the sound sequence supplied by the audio source 24 provides a

  simultaneous control of speaker 22 and source 28 of mechanical excitation

  Picnic. When moving the moving element 38, the force applied to the

  rear face 16 of the telephone is transmitted by the suction cup 62 to the plate 64.

  Under the action of this force, the plate 64 is caused to vibrate, thus generating an acoustic wave. The plate 64 then acts as a membrane

on the ambient air.

  In this embodiment, the control signal is integrated twice with respect to time before being applied to the source 28 of mechanical excitation. The deformation of the plate 64 is proportional to the force applied by the source 28 of mechanical excitation. The acoustic wave created by the deformation of the plate 64 is proportional to the speed of deformation thereof. The acoustic wave created is therefore the second derivative with respect to the

  time of the electrical signal applied to the acoustic excitation source.

  As the electrical signal applied to the source of excitation me-

  canonical is the double integral with respect to time of the control signal supplied by the audio source 24 after filtering, the acoustic wave produced by the vibration of the plate 64 is proportional to the control signal produced

by audio source 24.

  The double integrator 60 provides a frequency response

  optimal. However, this double integrator requires considerable travel

  bearing of the moving assembly 38 in the source 28 of mechanical excitation.

  In order to avoid excessive stress on the source 28 of mechanical excitation

  that the double integrator 60 can be omitted. Its removal leads to

  an increasing frequency response of 12 dB per octave for example.

  The presence of the cushion 66 between the housing 12 of the mobile phone and the plate 64 makes it possible to avoid detachment of the mobile phone and therefore

the existence of shock noise.

  Similarly, the presence of the suction cup 62 prevents such detachment

  when the total mass of the mobile phone is insufficient.

  The suction cup can be replaced by any other means of securing

  tion of the source 28 of mechanical excitation to the plate 24. These means can be constituted for example by a screw, a hook, a lug of

bonding or adhesive means.

  In the illustrated embodiment, the suction cup is arranged in line with the source of mechanical excitation. However, if the chassis consisting, in the example considered, of the rear face of the mobile phone is very rigid, the

  suction cup can be placed away from the source of mechanical excitation.

  Such an arrangement thus makes it possible to amplify the force applied to the plate 64 by a lever arm effect. The chassis of the telephone then constitutes a lever articulated at the point of contact of the telephone on the plate, the source 28 of mechanical excitation applying a force on the lever at a first point, which force is retransmitted to the plate 64 by the suction cup in a second point spaced from the point of articulation.

  It is clear that any type of portable electrical device, in addition to tele-

  mobile phone described above, can implement the invention such as a portable computer, a portable electronic agenda, a portable television or even a device performing at least one of the functions

  specific to the devices mentioned above.

Claims (14)

  1.- Portable electric appliance (10), comprising: - a chassis (12);   - an audio source (24) adapted to generate a signal of com-   request representative of a sound sequence; and - sound reproduction means (20) comprising a loudspeaker (22) for transmitting sound connected to said audio source (24) for controlling it as a function of said control signal representative of a sound sequence, characterized in that said means (20) for sound reproduction include   a source (28) of mechanical excitation mechanically coupled to said chassis   sis (12) and connected to said audio source (24) for its piloting in function   of said control signal representative of a sound sequence.   2.- portable electric device (10) according to claim 1, character-   in that said source (28) of mechanical excitation comprises a source (36) of controlled force connected to said source (24) audio and a crew   (38) movable movable relative to said source (36) of controlled force   dée, said source (36) of controlled force being adapted to act on said moving element (38), said source (36) of controlled force and / or said   mobile equipment (38) being fixed to said chassis (12).   3.- portable electric apparatus (10) according to claim 2, charac-   se in that said source (28) of mechanical excitation is adapted for a   rectilinear movement of said mobile assembly (38).   4.- Portable electric appliance (10) according to any one of the res-   previous indications, characterized in that said source (28) of excitation   mechanical forms a resonant system.   5.- portable electric apparatus (10) according to claim 4 and the re-   vendication 2 or 3, characterized in that said source (28) of excitation   canique comprises a member (50) for elastic return of said equipment (38)   movable interposed between said source (36) of controlled force and said equilibrium mobile page (38).   6.- portable electric device (10) according to claim 4 or 5, ca-   characterized in that the resonant frequency of said resonant system is substantially equal to 100 Hz.   7.- Portable electric device (10) according to any one of the res-   dications 2 to 6, characterized in that said source (28) of mechanical excitation   that includes a damping member (49) interposed between said source   (36) of commanded force and said moving element (38).   8.- Portable electric appliance (10) according to any one of the res-   dications 2 to 7, characterized in that said means (20) for restitution   our include means for controlling said source (36) of force controlled as a function of a parameter representative of the displacement of said mobile equipment (38).   9.- Portable electric appliance (10) according to any one of the res-   previous indications, characterized in that said means (20) for restitution   sound system include a low pass filter (32) between said source (28) of ex-   mechanical quotation and said audio source (24).   10.- Portable electric appliance (10) according to any one of the   previous vendications, characterized in that said means (20) of sound reproduction comprise a double integrator (60) between said source   (28) of mechanical excitation and said audio source (24).   11.- Portable electric appliance (10) according to any one of the   previous vendications, characterized in that it comprises means (62)   for securing said chassis (12) to a resonant plate (64).   12.- portable electric apparatus (10) according to claim 11, charac-   terized in that said securing means comprise a suction cup (62) fixed to said chassis (12) and adapted to be applied against said plate (64) resonant.   13.- Portable electric appliance (10) according to any one of the   previous sales, characterized in that said chassis (12) has an external face (16) for gripping said portable electrical appliance, and in that said source (28) of mechanical excitation is applied to said   external gripping face (16).   14.- Portable electrical appliance according to any one of the claims   previous cations, characterized in that it is a device exercising at   minus one of the main functions specific to the group of devices   nant: - a mobile telephone (10); - a laptop; - a portable electronic agenda; - portable television.