TECHNICAL FIELD

The disclosure relates to an audio generating structure for an electronic apparatus, the audio generating structure comprising a printed circuit board, a magnet, and an electromagnetic coil.

BACKGROUND

The quality of audio is in strong correlation with the space available for the structure that generates the audio. As a consequence, prior art audio generating structures usually have either low-quality audio output, to keep the size of the electronic apparatus relatively small, or have an increased size, and hence increased apparatus size, to improve the quality of the audio.

It is a standard requirement today that electronic apparatuses such as tablets, laptops, mobile phones, and panel speakers are as thin as possible while still able to produce good-quality sound. Furthermore, the increasingly popular use of foldable displays requires audio components to be even smaller, or more particularly, thinner.

Audio is commonly generated using a structure comprising a voice coil actuator, i.e., a magnet and an electromagnetic coil. These components are, however, of sizes that make the mechanical architecture and the connections to the amplifier complicated to design and fit into a thin apparatus.

Hence, there is a need for an improved audio generating structure in particular suitable for electronic apparatuses having small form factors and/or being foldable.

SUMMARY

It is an object to provide an improved audio generating structure. 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 structure for an electronic apparatus, the audio generating structure comprising a printed circuit board comprising a plurality of superimposed layers and a throughgoing aperture extending through the layers; -a first audio membrane connected to a first surface of the printed circuit board; a magnet arranged at least partially within the throughgoing aperture, the magnet being configured to generate movement of the first audio membrane along an actuation axis by means of a magnetic field; and an electromagnetic coil arranged within the printed circuit board such that it circumscribes the throughgoing aperture, the electromagnetic coil extending within at least two of the layers of the printed circuit board, and the electromagnetic coil being configured such that manipulation of electrical current in the electromagnetic coil causes a change in the magnetic field, the change moving the magnet along the actuation axis.

This solution provides an improved audio generating structure for an electronic apparatus such as a tablet, a laptop, a mobile phone, or a panel speaker. The audio generating structure comprises a highly efficient magnet actuator that is more powerful with the same size and with the same power consumption than prior art magnet actuators, because the construction of the magnet actuator is able to provide more force. The voice coil arrangement can also provide more force in the same size due to the longer wire length of the voice coil. It is also possible to reduce the overall size of the audio generating structure due to the good actuating efficiency and use of space. The thickness of the audio generating structure may be as little as 1.5-2 times the thickness of the printed circuit board. Furthermore, the solution allows for an audio generating structure that has less a complicated mechanical architecture as well as requires less complicated assembly, since, e.g., flex/spring contacts are not required between components.

In a possible implementation form of the first aspect, the audio generating structure further comprises a second audio membrane connected to a second surface of the printed circuit board, the first surface and the second surface of the printed circuit board extending perpendicular to the actuation axis, the magnet being configured to generate movement of the second audio membrane along the actuation axis. This allows a structure that can generate audio in two directions without requiring separate front and back cavities.

In a further possible implementation form of the first aspect, the first audio membrane and/or the second audio membrane are arranged on opposite sides of the magnet and arranged to cover the throughgoing aperture. This allows a structure that can generate audio in two directions without requiring separate front and back cavities. In a further possible implementation form of the first aspect, the first audio membrane and/or the second audio membrane is attached to the printed circuit board by a fixation element, at least one of the fixation element, the first audio membrane, and the second audio membrane being configured to allow the first audio membrane and/or the second audio membrane to at least partially move along the actuation axis in response to movement of the magnet. The fixation element allows simple assembly of the audio generating structure using as few components as possible.

In a further possible implementation form of the first aspect, the first audio membrane and/or the second audio membrane comprises a section configured to allow expansion and contraction of the membrane along the actuation axis, reducing the need for a separate element allowing movement of the first audio membrane and/or the second audio membrane.

In a further possible implementation form of the first aspect, the fixation element is an elastic and/or adhesive element, such that the fixation element allows simple assembly as well as facilitate movement of the audio membrane.

In a further possible implementation form of the first aspect, the audio generating structure comprises a second elastic element configured to connect the magnet to the printed circuit board, the second elastic element being configured to allow the magnet to move along the actuation axis. Such a solution allows the magnet to move as well as being held in place.

In a further possible implementation form of the first aspect, the magnet is fixed to a surface of at least one of the first audio membrane and the second audio membrane, ensuring the magnet is held into place and the audio membrane(s) to move in direct response to movement of the magnet.

In a further possible implementation form of the first aspect, the magnet is arranged in nesting configuration with the electromagnetic coil within a main plane of the printed circuit board. This allows a thinner magnet and coil solution which can be designed for, e.g., standard 8 inductive load and to be driven with a standard audio amplifier.

In a further possible implementation form of the first aspect, the electromagnetic coil comprises a plurality of planar sections, each planar section extending within one layer of the printed circuit board and the planar sections being superimposed on top of each other. This allows the voice coil to have a longer wire length, making the audio generating structure more powerful and efficient without increasing power consumption.

In a further possible implementation form of the first aspect, the electromagnetic coil comprises at least 10 planar sections. The larger the number of planar sections, the smaller the footprint of the printed circuit board can be.

In a further possible implementation form of the first aspect, each planar section of the electromagnetic coil follows a spiral path, each spiraled planar section extending in a plane parallel to the main plane. The spiral shape allows an increased number of coil loops within one plane.

In a further possible implementation form of the first aspect, each spiraled planar section of the electromagnetic coil comprises 10 to 20 spiral loops. The smaller the number of spiral loops, the closer the electromagnetic coil is to the magnet and the stronger the generated magnetic field can be.

In a further possible implementation form of the first aspect, adjacent layers of the printed circuit board are interconnected by vias extending in directions parallel with the actuation axis, each via forming a passage configured to accommodate the electromagnetic coil, and wherein the electromagnetic coil is arranged such that a spiraled planar section extending within one layer of the printed circuit board is connected to a corresponding spiraled planar section extending within an adjacent layer of the printed circuit board by a linear section of electromagnetic coil extending through one via, facilitating a simple way of arranging the electromagnetic coil in stacked layers by using current printed circuit board manufacturing methods.

In a further possible implementation form of the first aspect, each spiraled planar section, arranged in a layer of the printed circuit board enclosed by two adjacent layers, is connected to a first spiraled planar section arranged in a first adjacent layer by a first linear section of electromagnetic coil extending through a first via aligned with an outermost spiral loop of the first spiraled planar section of electromagnetic coil, and connected to a second spiraled planar section arranged in a second adjacent layer by a second linear section of electromagnetic coil extending through a second via aligned with an innermost spiral loop of the second spiraled planar section of electromagnetic coil, allowing all planar sections of electromagnetic coil to be interconnected and have the same number of loops.

In a further possible implementation form of the first aspect, the audio generating structure further comprises an audio-signal amplifier configured to move the magnet by means of audio signals, facilitating output of high-quality audio signals.

According to a second aspect, there is provided an electronic device comprising the audio generating structure according to the above. The audio generating structure facilitates an electronic apparatus capable of high-quality audio output. Due to the improved audio generating structure, the electronic apparatus can either have a smaller size or maintain the size but improve the sound pressure level.

These 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 cross-sectional view of an audio generating structure in accordance with an example of the embodiments of the disclosure;

Fig. 2 shows a cross-sectional view of an audio generating structure in accordance with an example of the embodiments of the disclosure;

Fig. 3 shows a partial cross-sectional view of a printed circuit board of an audio generating arrangement in accordance with an example of the embodiments of the disclosure;

Fig. 4 shows a top view of an audio generating structure in accordance with an example of the embodiments of the disclosure.

DETAILED DESCRIPTION

The present invention relates to an electronic apparatus comprising an audio generating structure 1 described in more detail below. The electronic apparatus may be a tablet, laptop, mobile phone, a speaker such as a panel speaker, or any electronic apparatus that requires high- quality audio to be generated by a structure taking up relatively little space. The present invention also relates to an audio generating structure 1 for an electronic apparatus, the audio generating structure 1 comprising a printed circuit board 2 comprising a plurality of superimposed layers 2a, 2b, 2c and a throughgoing aperture 3 extending through the layers 2a, 2b, 2c; a first audio membrane 4 connected to a first surface of the printed circuit board 2; a magnet 5 arranged at least partially within the throughgoing aperture 3, the magnet 5 being configured to generate movement of the first audio membrane 4 along an actuation axis A by means of a magnetic field; and an electromagnetic coil 6 arranged within the printed circuit board 2 such that it circumscribes the throughgoing aperture 3, the electromagnetic coil 6 extending within at least two of the layers 2a, 2b, 2c of the printed circuit board 2, and the electromagnetic coil 6 being configured such that manipulation of electrical current in the electromagnetic coil 6 causes a change in the magnetic field, the change moving the magnet 5 along the actuation axis A.

The audio generating structure 1 comprises a printed circuit board 2 comprising a plurality of superimposed layers 2a, 2b, 2c, a so-called multilayer PCB, as shown in Fig. 3 A throughgoing aperture 3 extends through the layers 2a, 2b, 2c, as shown in Figs. 1, 2, and 4.

A first audio membrane 4 is connected to a first surface of the printed circuit board 2, such as a top surface or a bottom surface, as illustrated in Fig. 2.

A magnet 5 is arranged at least partially within the throughgoing aperture 3. Magnet 5 is, in other words, configured to fit, and be movable, within throughgoing aperture 3. Magnet 5 may be configured such that the outer diameter magnet 5 is somewhat smaller than the inner diameter of throughgoing aperture 3.

The magnet 5 is configured to generate movement of the first audio membrane 4 along an actuation axis A by means of a magnetic field. The displacement of the first audio membrane 4 generates audio waves and produces high-quality audio output.

The audio generating structure 1 may further comprise an audio-signal amplifier 12 configured to move the magnet 5 by means of audio signals. An electromagnetic coil 6 is arranged within the printed circuit board 2 such that it circumscribes the throughgoing aperture 3, in other words, the electromagnetic coil 6 is integrated with the printed circuit board 2.

The magnet 5 may be arranged in nesting configuration with the electromagnetic coil 6 within a main plane Pl of the printed circuit board 2. There may be an air gap between the magnet 5 and the printed circuit board 2 and/or electromagnetic coil 6, e.g. 0.2 mm wide. The magnet may be cylindrical, and hence the throughgoing aperture 3 may be round, however, other shapes are also possible.

The electromagnetic coil 6 is configured such that manipulation of electrical current in the electromagnetic coil 6 causes a change in the magnetic field, the change in magnetic field moving the magnet 5 along the actuation axis A. Hence, first audio membrane 4 also moves along actuation axis A.

The electromagnetic coil 6 extends within at least two of the layers 2a, 2b, 2c of the printed circuit board 2.

The electromagnetic coil 6 may comprise a plurality of planar sections 6a, 6b, 6c, each planar section 6a, 6b, 6c extending within one layer 2a, 2b, 2c of the printed circuit board 2 and the planar sections 6a, 6b, 6c being superimposed on top of each other. The electromagnetic coil 6 may comprise at least 10 planar sections 6a, 6b, 6c. However, any suitable number of planar sections 6a, 6b, 6c is possible, though presumably there will be less than 50 layers 2a, 2b, 2c of the printed circuit board 2 and hence less than 50 planar sections 6a, 6b, 6c. The larger the number of layers 2a, 2b, 2c and planar sections 6a, 6b, 6c, the smaller the footprint of the printed circuit board 2 can be.

Each planar section 6a, 6b, 6c of the electromagnetic coil 6 may follow a spiral path, each spiraled planar section 6a, 6b, 6c extending in a plane P2 parallel with the main plane Pl, as illustrated on Fig. 3. Each spiraled planar section of the electromagnetic coil 6 may comprise 10 to 20 spiral loops 10. The closer the electromagnetic coil is to the magnet 5, the stronger the generated magnetic field is. Hence, a lower number of spiral loops 10 may be desirable, although any suitable number of spiral loops 10 is conceivable. The number of spiral loops 10 in total, in all layers 2a, 2b, 2c, may be between 100-150 in order to achieve the needed inductance and electromagnetic force.

For example, the wire may have a width of 100 pm and a thickness of 20 pm. The clearance between adjacent loops 10 within a layer may be 100 pm. Each layer 2a, 2b, 2c of the printed circuit board 2 may comprise an insulation layer having a thickness of 60 pm and a folio-layer having a thickness of 20 pm.

Any suitable number of adjacent layers 2a, 2b, 2c of the printed circuit board 2 may be interconnected by vias 11 extending in directions parallel with the actuation axis A. Each via 11 forms a passage configured to accommodate a section of the electromagnetic coil 6. The electromagnetic coil 6 may be arranged such that a spiraled planar section 6a, 6b, 6c extending within one layer 2a, 2b, 2c of the printed circuit board 2 is connected to a corresponding spiraled planar section 6a, 6b, 6c extending within an adjacent layer 2a, 2b, 2c of the printed circuit board 2 by a linear section 6d, 6e of electromagnetic coil 6 extending through one via 11.

As shown in Fig. 3, each spiraled planar section 6b, arranged in a layer 2b of the printed circuit board 2 enclosed by two adjacent layers 2a, 2c, may be connected to a first spiraled planar section 6a arranged in a first adjacent layer 2a by a first linear section 6d of electromagnetic coil 6 extending through a first via I la aligned with an outermost spiral loop 10a of the first spiraled planar section 6a of electromagnetic coil 6. Correspondingly, each spiraled planar section 6b may be connected to a second spiraled planar section 6c arranged in a second adjacent layer 2c by a second linear section 6e of electromagnetic coil 6 extending through a second via 1 lb aligned with an innermost spiral loop 10b of the second spiraled planar section 6c of electromagnetic coil 6.

The audio generating structure 1 may comprise a second audio membrane 7 connected to a second surface of the printed circuit board 2, as shown in Fig. 1. The first surface and the second surface of the printed circuit board 2 may extend perpendicular to the actuation axis A. The first surface and the second surface of the printed circuit board 2 may extend in parallel and form the top surface and the bottom surface of the printed circuit board 2. The magnet 5 may be configured to generate movement of the second audio membrane 7 along the actuation axis A, such that the first audio membrane 4 as well as the second audio membrane 7 can move along the actuation axis A.

The first audio membrane 4 and the second audio membrane 7 may be arranged on opposite sides of the magnet 5. The first audio membrane 4 and/or the second audio membrane 7 may be arranged to cover the throughgoing aperture 3 such that the throughgoing aperture 3 forms a void enclosed by the printed circuit board, the first audio membrane 4, and/or the second audio membrane 7.

The first audio membrane 4 and/or the second audio membrane 7 may be attached to the printed circuit board 2 by a fixation element 8, as shown in Figs. 1 and 2. At least one of the fixation element 8, the first audio membrane 4, and the second audio membrane 7 may be configured to allow the first audio membrane 4 and/or the second audio membrane 7 to at least partially move along the actuation axis A in response to movement of the magnet 5. IN other words, the fixation element 8 as well as the first audio membrane 4 and the second audio membrane 7 may have elastic properties.

In one embodiment, the first audio membrane 4 and/or the second audio membrane 7 comprises a section configured to allow at least partial expansion and contraction of the membrane 4, 7 along the actuation axis A. The section may for example have a spring-like shape allowing movement of a part of the membrane 4, 7.

In a further embodiment, the fixation element 8 is a first elastic and/or adhesive element. The fixation element 8 may be adhesive tape.

The audio generating structure 1 may also comprise a second elastic element 9 configured to connect the magnet 5 to the printed circuit board 2, as illustrated in Fig. 2. The second elastic element 9 is configured to allow the magnet 5 to move along the actuation axis A.

The fixation element 8 and/or the second elastic element 9 may have mechanical functions which are to keep the audio generating structure 1 together in every direction (x, y, z) and/or to provide spring-loaded freedom of movement. The magnet 5 may be fixed to a surface of at least one of the first audio membrane 4 and the second audio membrane 7, for example, the innermost surface of each membrane that faces the top surface or bottom surface of the printed circuit board 2.

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. 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.

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.