Patent Description:
In a headphone comprising separate left and right headphone devices (sometimes called "earphones") with corresponding ear cushions, the acoustic characteristics of the respective headphone devices depend both on the characteristics of the components of the headphone speaker housings (for instance on the performance of the electro-acoustic transducer, also called the "speaker", as well as on possible acoustical and electronic signal processing means such as frequency response equalizers or active noise cancelling means as well as on the acoustic characteristics of the ear cushion, when this is attached to the headphone speaker housing. In high-quality sound reproduction via such headphones it is important that the correct ear cushion and the correct placement of this ear cushion on the corresponding headphone speaker housing is always ensured and that for instance application of a left ear cushion on a right headphone speaker housing and vice versa can be avoided with certainty.

Prior art document <CIT> discloses a headset comprising an earphone and a corresponding ear cushion. In the region of the earphone that faces the ear cushion, the earphone is provided with a number of permanent magnets and in the corresponding side of the ear cushion there is provided a circumferentially extending ring-shaped plate member made of a soft magnetic material, such that the ear cushion can be held attached to the earphone by the magnetic forces acting between the magnets and the ring-shaped member. It is mentioned as an option that the ring-shaped member could also be a permanent magnet. This document does not describe means for ensuring that the angular orientation of the ear cushion is always correct relative to the earphone and as the embodiments shown in this document either used a circular earphone and similar ear cushion or a quadratic earphone and similar ear cushion, the issue of angular orientation of the ear cushion on the earphone is not addressed in the headset described in <CIT>. Further, in this document means for preventing the placement of for instance the right ear cushion on the left earphone and vice versa are not disclosed.

Documents <CIT>, <CIT> and <CIT> form further prior art relevant to the claimed subject-matter.

On the above background, it is an object of the invention to provide a headphone with non-interchangeable attachment of left and right ear cushions on the corresponding left and right headphone speaker housings, respectively.

It is a further object of the invention to provide a headphone that ensures that the left (L) and right (R) markings inside the ear cushions (if available) are placed correctly, and thereby ensuring that the user wears the headphones correctly, i.e. that the left headphone speaker housing and corresponding ear cushion is placed on the user's left ear and the right headphone speaker housing and corresponding ear cushion is placed on the user's right ear.

It is a further object of the invention to provide a headphone that ensures that the correct ear cushion always is placed on the correct headphone speaker housing, to maintain the correct electro-acoustical calibration (by tuning the DSP software or otherwise) as originally done in the factory. This is particularly important if the headphones have ANC (Active Noise Cancellation), where the small differences in ear cushions have great influence on the performance of the ANC. But also without ANC, calibration of the headphones to eliminate differences between left and right may be applied, in which case the influence of the ear cushions cannot be neglected and interchanging the left and right ear cushion would render the calibration worthless.

It is a further object of the invention to provide a headphone that ensures that the orientation of both the left and right ear cushions is correct in case of rotation symmetrically shaped ear cushions.

It is a further object of the invention to provide a headphone that insures a correct and precise positioning of the ear cushions on the headphone speaker housings.

The left and right ear cushions according to the invention can be manufactured using injection moulding using one and the same mould and can then be differentiated between left and right merely by the orientation of the magnets to be mounted in the ear cushions. This avoids a need for a mechanical differentiation between the left and right ear cushion which would be needed to avoid interchanging the left and right ear cushion by mistake. This mechanical difference would incur significant additional costs related to a second mould.

In the following, the term "headphone device" is used for the combination of (<NUM>) the headphone speaker housing, i.e. the part of the device that contains the electro-acoustic transducer or transducers as well as optional acoustical and electronic signal processing means such as frequency shaping filter means and/or active noise cancelling means and (<NUM>) the ear cushion, i.e. the portion of the device that connects the headphone speaker housing with the surface of the user's head. Further, a "headphone" is defined as a device that comprises at least one, but typically two headphone devices, typically a left headphone device and a right headphone device.

The above and further objects and advantages are according to a first aspect of the invention obtained by a headphone device according to claim <NUM>.

The above and further objects and advantages are according to a second aspect of the invention obtained by a headphone according to claim <NUM>.

Preferred embodiments of the first and second aspects of the invention are defined in the dependent claims.

Further benefits and advantages of the present invention will become apparent after reading the detailed description of non-limiting exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein.

In the following a detailed description of an example embodiment of the invention is given. It is, however understood that the principles of the invention could be embodied in other ways.

With reference to <FIG> there is shown a schematic cross-sectional view of a headphone device according to the invention generally indicated by reference numeral <NUM> and comprising a speaker housing <NUM> and ear cushion <NUM> according to an embodiment of the invention. The ear cushion <NUM> comprises an ear cushion body <NUM> attached to an ear cushion side portion <NUM> in which a plurality of permanent magnets <NUM>, <NUM> are provided. In the embodiment shown in <FIG>, the polarity of the two magnets <NUM>, <NUM> shown in the figure is as indicated, i.e. with the south pole facing the speaker housing <NUM>. The opposite polarity of the shown magnets could also be used as shown in <FIG> in the magnets <NUM>, <NUM>, <NUM>, <NUM>. The opposing magnets <NUM>, <NUM> and <NUM>, <NUM> respectively thus attract each other and the ear cushion <NUM> is therefore attached releasably to the speaker housing <NUM>. The interface between the ear cushion <NUM> and the speaker housing <NUM> is - in the shown embodiment - the plane end surface <NUM> of the ear cushion <NUM> and the corresponding plane end surface <NUM> of the speaker housing <NUM>, but it is understood that other configurations of the interface could also be used. In the speaker housing <NUM> there is provided an electro-acoustic transducer <NUM> (a "speaker") that converts an electric audio input signal to an acoustic output signal and thereby generates a sound field in the channel <NUM> in the speaker housing <NUM> and the cooperating channel <NUM> in the ear cushion <NUM>.

The objects of the invention outlined above are according to the invention obtained by specific polarities of the magnets provided in the ear cushion and the speaker housing, respectively. This is illustrated by the non-limiting example shown in <FIG>, but it is emphasized that other distributions, numbers and specific polarities could also be used and that these would fall within the scope of the invention as defined by the claims.

<FIG> shows an ear cushion <NUM> according to an embodiment of the invention seen from the plane end surface <NUM> and a speaker housing <NUM> according to the same embodiment of the invention seen from plane end surface <NUM>. Both the ear cushion <NUM> and the speaker housing <NUM> are symmetrical about the perpendicular respective x and y axes (X, YC, YE) that subdivides the ear cushion <NUM> and the speaker housing <NUM> into four portions, each of which comprises one magnet <NUM>, <NUM>, <NUM>, <NUM> and <NUM>, <NUM>, <NUM>, <NUM>, respectively. In or behind the end surface <NUM> there are provided four permanent magnets <NUM>, <NUM>, <NUM>, <NUM>. The polarity of the magnets is indicated in the figure. Magnets <NUM>, <NUM> and <NUM> have their respective south poles S1c, S2c and S3c pointing outwards from the end surface <NUM>, such that they face the end surface <NUM> of the speaker housing, when the ear cushion and speaker housing are assembled. The fourth magnet <NUM> has the opposite polarity, i.e. the north pole Nc points outwards from the end surface <NUM>. In or behind the end surface <NUM> of the speaker housing <NUM>, four magnets <NUM>, <NUM>, <NUM>, <NUM> are positioned such that they correspond with the magnets <NUM>, <NUM>, <NUM> and <NUM> in the ear cushion <NUM>. As it appears from the figure, the polarities for the magnets <NUM>, <NUM>, <NUM>, <NUM> are opposite to the polarities of the magnets <NUM>, <NUM>, <NUM>, <NUM>, forming attracting magnet pairs <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM>, and the ear cushion <NUM> will hence be kept attached to the speaker housing <NUM> by the magnetic forces of the respective pairs of magnets, when the ear cushion <NUM> is correctly fitted on the speaker housing <NUM>. If it is attempted to fit the speaker housing <NUM> to the ear cushion <NUM> rotated by <NUM> degrees as indicated by arrow R, different magnets will be opposing each other and the respective polarities of the pairs of magnets <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM> will no longer all match (two will match and two will not match) and the respective magnetic forces will repel the ear cushion <NUM> from its correct position on the speaker housing <NUM>. In this manner it is according to the principles of the invention ensured that the ear cushion <NUM> is always correctly fitted to the speaker housing <NUM>.

It is emphasized that although the embodiment of the invention shown in <FIG> has specifically one magnet located in each of the portions defined by the respective x and y axes, this is not a limitation, and the invention also covers other numbers and/or positions of the magnets <NUM>, <NUM>, <NUM>, <NUM> and <NUM>, <NUM>, <NUM>, <NUM> on the respective end surfaces <NUM> and <NUM>. The basic principle of the invention is that the polarities and positions of the magnets are chosen such that it only allows one correct fitting of the ear cushion <NUM> on the speaker housing <NUM>. This basic principle of the invention will be reverted to with reference to <FIG> and <FIG> below.

With reference to <FIG> there is shown a schematic partly cross-sectional view of an embodiment of an ear cushion according to the invention. <FIG> shows the ear cushion body <NUM> surrounding the sound opening <NUM>. <FIG> is a cross sectional view along line A-A in <FIG> in the direction indicated by the arrows A showing the ear cushion body <NUM> attached by suitable attachment means <NUM> to a circumferential plate member <NUM> extending circumferentially all the way round the sound opening <NUM> and provided with permanent magnets <NUM>. Above the plate member <NUM> there is provided a protective and sound permeable screen <NUM>. The plate member <NUM> is further provided with outwardly extending aligning tap members <NUM>.

With reference to <FIG> there is shown the ear cushion shown in <FIG> seen from the side facing the speaker housing. Two tap members <NUM> are provided on the circumferentially extending plate member <NUM> behind which the magnets <NUM> are provided.

With reference to <FIG> there is shown the ear cushion shown in <FIG>. <FIG> shows a schematic side view of the ear cushion body <NUM> and the plate member <NUM> that towards the ear cushion body <NUM> is provided with the magnets (not shown in <FIG> is a cross-sectional view along line B - B in <FIG> seen from the side facing the speaker housing. The four magnets <NUM> that are used in this embodiment are shown.

With reference to <FIG> there is shown an embodiment of a speaker housing seen from the side (a) and from above (b) in a cross-sectional view along the line C - C in <FIG> seen in the direction indicated by the arrows C (seen from the side facing the ear cushion). The speaker housing comprises an upper section <NUM> forming a smooth transition to the ear cushion and a portion <NUM> that among others may comprise the electro-acoustic transducer ("speaker") of the headphone device. In <FIG> the four magnets <NUM> are shown placed at positions corresponding to the magnets <NUM> in the ear cushion shown in <FIG>. Two inwardly extending alignment tap members <NUM> are also shown, which can engage with corresponding alignment means <NUM> of the ear cushion as shown in <FIG>.

With reference to <FIG> there is shown a schematic perspective view of a headphone <NUM> according to an embodiment of the invention comprising a left headphone device L having a left speaker housing <NUM> and a corresponding left ear cushion <NUM> and a right headphone device R having a right speaker housing <NUM> and a right ear cushion <NUM>. The left and right headphone devices L, R are connected by a headband <NUM>.

With reference to <FIG> and <FIG> the advantageous effects of the headphone device and headphone according to the invention is explained. The figures illustrate the effect of different magnet configurations both in the headphone device and in the entire headphone according to the invention.

<FIG> shows a magnet configuration that does not prevent a wrong orientation of the respective left and right ear cushion on the corresponding speaker housing and that does also not prevent interchanging of the left and right ear cushions.

<FIG> shows a magnet configuration that does prevent interchanging of the left and right ear cushions but does not prevent a wrong orientation of the ear cushions. In <FIG>, all of the four magnets <NUM>, <NUM>, <NUM>, <NUM> in the left (L) speaker housing have the same polarity and this polarity is opposite to the polarity of the corresponding magnets <NUM>, <NUM>, <NUM>, <NUM> in the right (R) speaker housing.

<FIG> shows a magnet configuration according to an embodiment of the invention. With reference to (a) of <FIG>, this configuration ensures that both position and orientation of the ear cushions I and II respectively are correct on the respective two speaker housings III and IV. It is understood that also the opposite polarities of all of the shown magnets shown in <FIG> would constitute an embodiment of the invention. In <FIG>, one (magnet <NUM>) of the four magnets <NUM>, <NUM>, <NUM>, <NUM> in the left (L) speaker housing has the opposite polarity and this of the other three magnets <NUM>, <NUM>, <NUM> and the polarity of the magnets <NUM>, <NUM>, <NUM>, <NUM> respectively is opposite to the polarity of the corresponding magnets <NUM>, <NUM>, <NUM>, <NUM> in the right (R) speaker housing. In <FIG> (and this also applies to <FIG>, although not actually shown in these figures) the headphone is defined by an axis of symmetry S about which the first and second headphone devices (L, R) are located.

Claim 1:
A headphone device comprising
a speaker housing (<NUM>) and
an ear-cushion (<NUM>),
the speaker housing (<NUM>) comprising a speaker housing side portion (<NUM>) and
the ear cushion (<NUM>) comprising an ear cushion side portion (<NUM>),
where the speaker housing side portion (<NUM>) and the ear cushion side portion (<NUM>) respectively are configured for releasable connection to each other along an end surface (<NUM>) of the ear cushion side portion (<NUM>) and a corresponding end surface (<NUM>) of the speaker housing side portion (<NUM>),
wherein:
- said speaker housing side portion (<NUM>) comprises a plurality of first permanent magnets (<NUM>, <NUM>, <NUM>, <NUM>) provided at respective first locations on or in the speaker housing side portion (<NUM>) with each respective magnet generating a magnetic field
- said ear cushion side portion (<NUM>) comprises a plurality of second permanent magnets (<NUM>, <NUM>, <NUM>, <NUM>) provided at respective second locations on or in the ear cushion side portion (<NUM>) with each respective magnet generating a magnetic field
- where each of said first locations respectively corresponds substantially to one of said second locations; and
- where for each pair of said first and second permanent magnets (<NUM>-<NUM>; <NUM>-<NUM>; <NUM>-<NUM>; <NUM>-<NUM>), the polarity of the magnetic pole of a first permanent magnet (<NUM>, <NUM>, <NUM>, <NUM>), provided at one of said first locations and which pole of the first permanent magnet faces the corresponding second permanent magnet is opposite to the polarity of the magnetic pole of the corresponding second permanent magnet (<NUM>, <NUM>, <NUM>, <NUM>) provided at the corresponding of said second locations and which pole of the second permanent magnet faces the first permanent magnet, when the end surface (<NUM>) of the speaker housing side portion (<NUM>) of the speaker housing (<NUM>) and the end surface (<NUM>) of the ear cushion side portion (<NUM>) of the ear cushion (<NUM>) are aligned and in contact with each other;
- characterized in that
- the polarity of at least one magnet in the ear cushion side portion (<NUM>) is different from the polarity of the remainder of the magnets in the ear cushion side portion (<NUM>).