WO2021170220A1

WO2021170220A1 - Audio generating arrangement and electronic device comprising such arrangement

Info

Publication number: WO2021170220A1
Application number: PCT/EP2020/054924
Authority: WO
Inventors: Ossi Maenpaa
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2020-02-25
Filing date: 2020-02-25
Publication date: 2021-09-02

Abstract

An audio generating arrangement (1) for an electronic device (2), the arrangement (1) comprising an audio signal transmitter (3), a first audio radiating membrane (4) and a second audio radiating membrane (5) configured to be controlled separately, and a first control arrangement (6) and a second control arrangement (7) for controlling oscillations (8, 9) of the first audio radiating membrane (4) and the second audio radiating membrane (5), the oscillations (8, 9) generating audio. The first control arrangement (6) is configured to receive a first audio signal from the audio signal transmitter (3), and the first audio signal is configured to generate first oscillations (8) in the first audio radiating membrane (4). The second control arrangement (7) is configured to receive a second audio signal from the audio signal transmitter (3), and the second audio signal being configured to generate second oscillations (9) in the second audio radiating membrane (5). One of the first audio signal and the second audio signal is delayed in relation to the other, such that the first oscillations (8) and the second oscillations (9) are one of in phase or in reverse phase. This solution provides an audio generating arrangement that is able to adjust sound difference between the display and back-cover of an electronic device in order to minimize privacy leakage when device is used against ear, but also to maximize sound pressure level towards user when the device is used in loudspeaker mode.

Description

AUDIO GENERATING ARRANGEMENT AND ELECTRONIC DEVICE COMPRISING

SUCH ARRANGEMENT

TECHNICAL FIELD

The disclosure relates to an audio generating arrangement, more particularly to an audio generating arrangement for an electronic device.

BACKGROUND

An ongoing problem with electronic devices, such as mobile phones, is the leaking of audio signals, which increases the possibility of breaching speech privacy. Receivers are nowadays placed close to the upper ends of mobile phones in order to maximize the size of display. As a result, when a device is placed against ear, a big part of the audio signals is leaking to the surroundings, thus risking privacy. The same leakage happens when electronic devices or mobile phones are equipped with audio displays. In that case, earpiece sound hotspot is closer to the middle of the display. In this configuration, air-conducted audio leakage over the phone edges is small; majority of leakage sound is generated by a back cover vibration of the device. Audio displays can also be used in loudspeaker mode to allow handsfree call, video call or listening of music, i.e. device is not held against ear. In these cases, the main challenge is to make the audio display loud enough towards user (display direction) but not to radiate sound in other directions.

The receivers and loudspeakers of the majority of the phones manufactured nowadays are equipped with dedicated sound radiating membranes, integrated in the device in sealed cavities and sound holes. However, these are problematic, since these holes make the device vulnerable for dust, water etc. impurities.

Currently, an often-used solution is implementing traditional electromagnetic receivers, when sound holes are located so near to the upper edge of the electronic device that even when the device is placed against ear, big part of acoustical energy is leaked out, thereby causing privacy problems. When using single-coil transducer to create singing display receiver, similar privacy leakage problem exists. When using traditional mobile phones in loudspeaker mode, sound is radiated in all directions, although sound energy should be pointed towards user, in display direction. SUMMARY

It is an object to provide an improved audio generating arrangement. The foregoing and other objects are achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description, and the figures.

According to a first aspect, there is provided an audio generating arrangement for an electronic device, the arrangement comprising an audio signal transmitter, a first audio radiating membrane and a second audio radiating membrane configured to be controlled separately, a first control arrangement and a second control arrangement for controlling oscillations of the first audio radiating membrane and the second audio radiating membrane, the oscillations generating audio, the first control arrangement being configured to receive a first audio signal from the audio signal transmitter, the first audio signal being configured to generate first oscillations in the first audio radiating membrane, the second control arrangement being configured to receive a second audio signal from the audio signal transmitter, the second audio signal being configured to generate second oscillations in the second audio radiating membrane, one of the first audio signal and the second audio signal being delayed in relation to the other, such that the first oscillations and the second oscillations are one of in phase or in reverse phase.

This solution provides an audio generating arrangement that is able to adjust sound difference between the display and back cover of an electronic device in order to minimize privacy leakage when device is used against ear, but also to maximize sound pressure level towards user when the device is used in loudspeaker mode. The audio generating arrangement can be mounted in portable electronic devices, such as mobile phones and tablets. The arrangement has a simple structure and comprises only a few elements, but can be used in multiple problematic areas, as described above. Furthermore, it is possible to use the arrangement effectively in different circumstances, since it is possible to optimize the delay times and set different delay times for each frequency band.

In a possible implementation form of the first aspect, the audio is amplified when the first oscillations and the second oscillations are in the same phase, and the audio is attenuated when the first oscillations and the second oscillations are in the reverse phase. This facilitates the adjustment of the oscillations and inherently the audio signal. This solution allows both the attenuation or even complete elimination of sound leakage and the amplification of audio signals in the display direction when in loudspeaker mode.

In a further possible implementation form of the first aspect, the delay of the second audio signal leads to attenuation of audio when the first oscillations and the second oscillations are in the reverse phase. When the oscillations are in reverse phase, it allows the second audio radiating membrane to create cancellation vibration, which prevents the second audio radiating membrane from creating an audible sound. This makes it possible to avoid sound leaking to other people in the surroundings of the device.

In a further possible implementation form of the first aspect, the first oscillations of the first audio radiating membrane have smaller amplitudes than the second oscillations of the second audio radiating membrane, allowing the first audio radiating membrane and/or the display of the electronic device to have a stiffer, more rigid structure than the second audio radiating membrane and/or the back cover of the device.

In a further possible implementation form of the first aspect, the first control arrangement is arranged between the first audio radiating membrane and the second control arrangement, and the second control arrangement is arranged between the second audio radiating membrane and the first control arrangement. This allows controlling the delay and/or phase difference with the first and second control arrangement between the two audio radiating membranes.

In a further possible implementation form of the first aspect, the first audio radiating membrane and the second audio radiating membrane are separated by a distance, the delay being adapted to the distance. During amplification, to maximize sound pressure level towards user, the first audio signal is delayed in order to get it in the same phase as the second audio signal, which is traveling longer distance. This provides maximum sound pressure level in first audio radiating membrane direction and attenuates sound in other directions. During attenuation, to reduce audible sound in the second audio radiating membrane direction, the second audio signal is delayed so that it creates second oscillations in an opposite phase compared to the phase of first oscillations. This facilitates the effective amplification or attenuation of the audio signals.

In a further possible implementation form of the first aspect, each of the first control arrangement and the second control arrangement comprises an actuator and/or a coil. Different types of actuators or coils may be used, allowing the user and/or manufacturer to set up and optimize the arrangement according to their preference or need.

According to a second aspect, there is provided an electronic device comprising a display, a back cover, and an audio generating arrangement, the display forming the first audio radiating membrane of the arrangement, the back cover forming the second audio radiating membrane of the arrangement. This solution provides an advanced, portable electronic device that can be effectively used in both loudspeaker and speech privacy mode. The electronic device provides its user with the possibility of audio attenuation in order to increase speech privacy; and audio amplification in order to increase sound pressure level, volume, sound quality and user experience.

In a possible implementation form of the second aspect, the electronic device comprises a dual direction actuator, allowing the device to have a thin structure, design.

In a further possible implementation form of the second aspect, the electronic device does not comprise a separate audio generating device, facilitating production of sounds and/or vibrations without needing additional, separate components.

According to a third aspect, there is provided a method of generating audio in an electronic device, the method comprising the steps of: a first control arrangement receiving a first audio signal from an audio signal transmitter, the first audio signal generating first oscillations in a first audio radiating membrane, a second control arrangement receiving a second audio signal from the audio signal transmitter, the second audio signal generating second oscillations in a second audio radiating membrane, one of the first audio signal and the second audio signal being received with a delay in relation to the other, such that the first oscillations and the second oscillations are generated one of in same phase or in reverse phase.

This solution provides a method that can be used in electronic devices, the method enabling audio amplification when the device is in loudspeaker mode, and enabling audio attenuation when the device is used in speech privacy mode, ergo when placed against ear.

In a possible implementation form of the third aspect, the method further comprises the first control arrangement controlling the first oscillations of the first audio radiating membrane, and the second control arrangement controlling the second oscillations of the second audio radiating membrane. This facilitates setting optimal tuning values, and the precise adjustment and controlling of the oscillations and audio signals.

In a further possible implementation form of the third aspect, when the first oscillations and the second oscillations are in the same phase, the audio is amplified, and when the first oscillations and the second oscillations are in the reverse phase, the audio is attenuated. This facilitates the effective adjustment of the audio, enabling both amplification and attenuation of the signals depending on the mode the device is in.

In a further possible implementation form of the third aspect, the audio is amplified by 3-6 dB and/or the audio is attenuated by 6-12 dB. This allows - in loudspeaker mode - the summary audio signal to be 3-6 dB louder than the audio that would be generated only by the first audio radiating membrane. Furthermore, this allows - in speech privacy mode - the audio to be 6-12 dB quieter than the audio that would be generated only by the first audio radiating membrane and then leaked on the edges of the device.

In a further possible implementation form of the third aspect, the first oscillations and the second oscillations are in phase when the electronic device is in a loudspeaker mode, and the first oscillations and the second oscillations are in reverse phase when the electronic device is in a speech privacy mode. This allows the device to be used in two modes, where the audio signal is advantageously adjusted in both modes. Furthermore, this enables the device to switch between the two modes, depending on whether the device is held against ear or is used in loudspeaker mode.

This and other aspects will be apparent from the embodiments described below.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present disclosure, the aspects, embodiments and implementations will be explained in more detail with reference to the example embodiments shown in the drawings, in which:

Fig. 1 shows a schematic cross-sectional side view of an electronic device comprising an audio generating arrangement in accordance with one embodiment of the present invention; Fig. 2 shows a detail of a cross-sectional view of an electronic device comprising an audio generating arrangement in accordance with one embodiment of the present invention;

Fig. 3 shows a schematic illustration of an audio generating arrangement in accordance with one embodiment of the present invention, when the oscillations are in phase;

Fig. 4 shows a schematic illustration of an audio generating arrangement shown in Fig. 3, when the oscillations are in reverse phase.

DETAILED DESCRIPTION

Figs. 1 and 2 illustrate an electronic device 2 comprising a display, a back cover, and an audio generating arrangement 1. The electronic device 2 may be a portable device, for example a mobile phone or a tablet. The electronic device 2 may be equipped with an audio display. The audio generating arrangement 1 comprises a first audio radiating membrane 4 and a second audio radiating membrane 5. The display of the electronic device 2 forms the first audio radiating membrane 4 of the arrangement 1, and the back cover forms the second audio radiating membrane 5 of the arrangement 1.

In a possible embodiment, the electronic device 2 comprises a dual-direction actuator. The dual-direction actuator comprises two coils and one magnet between the coils, which has the advantage of a thin structure. However, at least two piezo actuators, or other electromechanical vibrating actuators, may be used instead of a coil.-and-magnet dual-direction actuator. When using the latter, the magnet provides a non-vibrating support allowing the display and back cover to vibrate independently. When using e.g. piezo actuators, the actuators are to be placed between one of the above-mentioned audio radiating membranes 4, 5 and a non-vibrating mid- frame of the electronic device 2.

Preferably, the electronic device 2 does not comprise a separate audio generating device.

The electronic device 2 equipped with the audio generating arrangement 1 according to one embodiment is able to function in two modes when generating audio, i.e. in loudspeaker mode and in speech privacy mode, and is also able to switch between these modes based on the position of the device or user input, etc. When the electronic device 2 is in speech privacy mode, a relatively high amount of energy is required to create display vibration. The display vibration is created such that a first audio signal generates first oscillations 8 in the first audio radiating membrane 4, that is, the display. Part of the vibration energy is then also coupled to the back cover of phone through mechanical and magnetic coupling. This is done by feeding a second audio signal equal to the first audio signal to a second control arrangement 7 so that it generates second oscillations 9. The first oscillations 8 and the second oscillations 9 both generate audio. The second oscillations 9 create cancellation vibration to minimize sound leaking in the direction of the back cover of the device 2, that is, the second audio radiating membrane 5. The second control arrangement 7 is preferably located on the backside of the device 2, close to the back cover. When the electronic device 2 is in loudspeaker mode, the sound pressure level can be maximized, and the summary signal can be up to 6 dB louder than the audio that would be generated only by the first audio radiating membrane 4. This can be achieved by delaying the first audio signal, that is, the display-side audio signal, and bringing the first oscillations 8 and second oscillations 9 in phase.

The display side of the electronic device 2 is usually stiffer than the back cover of the device, so the configuration is set such that the difference in the rigidness does not influence the efficiency.

The audio generating arrangement 1 itself, that may be mounted in an electronic device 2 as described above, comprises an audio signal transmitter 3, a first audio radiating membrane 4 and a second audio radiating membrane 5. Moreover, it may also comprise a first control arrangement 6 and a second control arrangement 7. The first audio radiating membrane 4 and the second audio radiating membrane 5 are controlled individually and separately. The first control arrangement 6 controls the first oscillations 8 of the first audio radiating membrane 4, and the second control arrangement 7 controls the second oscillations 9 of the second audio radiating membrane 5. The first control arrangement 6 is able to receive a first audio signal from the audio signal transmitter 3, so that after the first audio signal can generate first oscillations 8 in the first audio radiating membrane 4. Similarly, the second control arrangement 7 is configured to receive a second audio signal from the audio signal transmitter 3, and then the second audio signal generates second oscillations 9 in the second audio radiating membrane 5. Either the first audio signal or the second audio signal is delayed in relation to the other. This delay puts the first oscillations 8 and the second oscillations 9 in phase or in reverse phase. The audio is amplified when the first oscillations 8 and the second oscillations 9 are in the same phase, this is depicted in Fig. 3. Amplification of the audio occurs when the device 2 is in loudspeaker mode. In the loudspeaker mode both display side and back cover side are used to produce the needed sound pressure level. The first audio signal is delayed to compensate for the longer travelling time of the second audio signal. As a result, the first and second audio signals generate oscillations 8, 9 at the same time, enabling the audio to be amplified and directed in the direction of the display and inherently the user. This way, the sound pressure level is maximized and the user experience is increased. The audio is attenuated when the first oscillations 8 and the second oscillations 9 are in the reverse phase, as shown in Fig. 4. Attenuation or in some cases even the full cancellation of the audio occurs when the device 2 is used in speech privacy mode, for example when placed against a user's ear. In the speech privacy mode, the same audio signal is fed to both the first audio radiating membrane 4 and the second audio radiating membrane 5. In this mode, the second audio signal is delayed in order to compensate the longer travelling time of the first audio signal. In this mode furthermore, the first oscillations 8 and the second oscillations 9 are in reverse phase. The anti-phase vibration created as described above prevents the back cover of the device 2 from leaking audible sound. However, the arrangement 1 may not in every configuration and/or situation be able to completely cancel the leakage, but preferably attenuates it by up to 14 or even by 20 dB.

The first oscillations 8 of the first audio radiating membrane 4 have smaller amplitudes than the second oscillations 9 of the second audio radiating membrane 5. This mostly applies when the display has a more rigid structure than the back cover of the electronic device 2.

As illustrated in Figs. 1 and 2, the first control arrangement 6 is arranged between the first audio radiating membrane 4 and the second control arrangement 7. Moreover, the second control arrangement 7 is arranged between the second audio radiating membrane 5 and the first control arrangement 6.

The first audio radiating membrane 4 and the second audio radiating membrane 5 are separated by a distance d, the delay being adapted to the distance d. The delay may also be set and optimized based on the frequency. Frequency-pending delay can be configured in both the first control arrangement 6 and the second control arrangement 7. Each of the first control arrangement 6 and the second control arrangement 7 can, in one embodiment, comprise an actuator and/or a coil. The actuator may be a piezo actuator or a dual direction actuator. In the latter, preferable case, the dual direction actuator includes two coils and a magnet. If using a dual direction actuator, it is possible to mount the audio generating arrangement 1 in an electronic device 2 that is approximately 10 mm thick. Instead of the dual direction actuator, it is also possible to use two single actuators, in which case both actuators include one coil and one magnet.

The method of generating audio in an electronic device 2 with an audio generating arrangement 1 comprises the following steps. The first control arrangement 6 receives a first audio signal from an audio signal transmitter 3, then the first audio signal generates first oscillations 8 in the first audio radiating membrane 4, which may be in one embodiment the display of the electronic device 2. A second control arrangement 7 receives a second audio signal from the audio signal transmitter 3, and similarly to the first audio signal, the second audio signal generates second oscillations 9 in the second audio radiating membrane 4. Either the first audio signal or the second audio signal is a delayed in relation to the other, resulting in the first oscillations 8 and the second oscillations 9 being in same phase or in reverse phase. Different delay time can be set for different frequencies.

The method may further comprise the step of the first control arrangement 6 controlling the first oscillations 8 of the first audio radiating membrane 4, and the second control arrangement 7 controlling the second oscillations 9 of the second audio radiating membrane 5. The control arrangements 6, 7 can set and/or change the nature of the oscillations 8, 9 in order to optimize the audio generation in both loudspeaker and speech privacy mode.

When the first oscillations 8 and the second oscillations 9 are in the same phase, the audio is amplified, the sound pressure level is maximized in the direction of the first audio radiating membrane 4. When the first oscillations 8 and the second oscillations 9 are in the reverse phase, the audio is attenuated in the direction of the second audio radiating membrane 5.

The audio may be amplified by 3-6 dB and/or the audio may be attenuated by 6-12 dB. However, in certain configurations the audio may be attenuated by 6-14 dB or even by 6-20 dB. The first oscillations 8 and the second oscillations 9 are in phase when the electronic device 2 is in a loudspeaker mode, and the first oscillations 8 and the second oscillations 9 are in reverse phase when the electronic device 2 is in a speech privacy mode. An illustration of this is shown in Figs. 3 and 4.

The various aspects and implementations have been described in conjunction with various embodiments herein. However, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed subject-matter, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

The reference signs used in the claims shall not be construed as limiting the scope. Unless otherwise indicated, the drawings are intended to be read (e.g., cross-hatching, arrangement of parts, proportion, degree, etc.) together with the specification, and are to be considered a portion of the entire written description of this disclosure. As used in the description, the terms “horizontal”, “vertical”, “left”, “right”, “up” and “down”, as well as adjectival and adverbial derivatives thereof (e.g., “horizontally”, “rightwardly”, “upwardly”, etc.), simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader. Similarly, the terms “inwardly” and “outwardly” generally refer to the orientation of a surface relative to its axis of elongation, or axis of rotation, as appropriate.

Claims

1. An audio generating arrangement (1) for an electronic device (2), said arrangement (1) comprising -an audio signal transmitter (3),

-a first audio radiating membrane (4) and a second audio radiating membrane (5) configured to be controlled separately,

-a first control arrangement (6) and a second control arrangement (7) for controlling oscillations (8, 9) of said first audio radiating membrane (4) and said second audio radiating membrane (5), said oscillations (8, 9) generating audio, said first control arrangement (6) being configured to receive a first audio signal from said audio signal transmitter (3), said first audio signal being configured to generate first oscillations (8) in said first audio radiating membrane (4), said second control arrangement (7) being configured to receive a second audio signal from said audio signal transmitter (3), said second audio signal being configured to generate second oscillations (9) in said second audio radiating membrane (5), one of said first audio signal and said second audio signal being delayed in relation to the other, such that said first oscillations (8) and said second oscillations (9) are one of in phase or in reverse phase.

2. The audio generating arrangement (1) according to claim 1, wherein said audio is amplified when said first oscillations (8) and said second oscillations (9) are in said same phase, and said audio is attenuated when said first oscillations (8) and said second oscillations (9) are in said reverse phase.

3. The audio generating arrangement (1) according to claim 1 or 2, wherein the delay of said second audio signal leads to attenuation of audio when said first oscillations (8) and said second oscillations (9) are in said reverse phase.

4. The audio generating arrangement (1) according to any of the previous claims, wherein said first oscillations (8) of said first audio radiating membrane (4) have smaller amplitudes than said second oscillations (9) of said second audio radiating membrane (5).

5. The audio generating arrangement (1) according to any of the previous claims, wherein said first control arrangement (6) is arranged between said first audio radiating membrane (4) and said second control arrangement (7), and said second control arrangement (7) is arranged between said second audio radiating membrane (5) and said first control arrangement (6).

6. The audio generating arrangement (1) according to any of the previous claims, wherein said first audio radiating membrane (4) and said second audio radiating membrane (5) are separated by a distance (d), said delay being adapted to said distance (d).

7. The audio generating arrangement (1) according to any of the previous claims, wherein each of said first control arrangement (6) and said second control arrangement (7) comprises an actuator and/or a coil.

8. An electronic device (2) comprising a display, a back cover, and the audio generating arrangement (1) according to any one of claims 1-7, said display forming the first audio radiating membrane (4) of the arrangement (1), said back cover forming the second audio radiating membrane (5) of the arrangement (1).

9. The electronic device (2) according to claim 8, wherein said electronic device (2) comprises a dual-direction actuator.

10. The electronic device (2) according to claim 8 or 9, wherein said electronic device (2) does not comprise a separate audio generating device.

11. A method of generating audio in an electronic device (2), said method comprising the steps of:

-a first control arrangement (6) receiving a first audio signal from an audio signal transmitter

(3), said first audio signal generating first oscillations (8) in a first audio radiating membrane

(4), ofi'WO 2021/170220 PCT/EP2020/054924

-a second control arrangement (7) receiving a second audio signal from said audio signal transmitter (3), said second audio signal generating second oscillations (9) in a second audio radiating membrane (4), one of said first audio signal and said second audio signal being received with a delay in relation to the other, such that said first oscillations (8) and said second oscillations (9) are generated one of in same phase or in reverse phase.

12. The method according to claim 11, wherein the method further comprises said first control arrangement (6) controlling said first oscillations (8) of said first audio radiating membrane (4), and said second control arrangement (7) controlling said second oscillations (9) of said second audio radiating membrane (5).

13. The method according to claim 11 or 12, wherein when said first oscillations (8) and said second oscillations (9) are in said same phase, said audio is amplified, and when said first oscillations (8) and said second oscillations (9) are in said reverse phase, said audio is attenuated.

14. The method according to claim 13, wherein said audio is amplified by 3-6 dB and/or said audio is attenuated by 6-12 dB.

15. The method according to any of claims 11 to 14, wherein said first oscillations (8) and said second oscillations (9) are in phase when said electronic device (2) is in a loudspeaker mode, and said first oscillations (8) and said second oscillations (9) are in reverse phase when said electronic device (2) is in a speech privacy mode.