WO2001030114A1

WO2001030114A1 - Loudspeaker

Info

Publication number: WO2001030114A1
Application number: PCT/NZ2000/000173
Authority: WO
Inventors: Christopher Colin Lock; John Frederick Corey; Graeme Oliver Jones; Kelly Charles Waterman
Original assignee: Slab Technology Limited
Priority date: 1999-10-18
Filing date: 2000-09-05
Publication date: 2001-04-26
Also published as: AU7461800A

Abstract

A loudspeaker with a planar diaphragm having photovoltaic means for use in remote locations or where power supply could be a problem. The loudspeaker can also have cordless operation.

Description

Title: LOUDSPEAKER

FIELD

This invention relates to a loudspeaker in particular but not exclusively to a loudspeaker having a planar diaphragm adapted for use in remote locations.

BACKGROUND

Loudspeakers with flat or planar diaphragms have been known for a number of years.

There have been many attempts to create flat panel speakers in order to save space such as the well-known electro static speakers which can be hung from a wall like a picture. Most prior art flat speakers have not been able to deliver performance on a cost-effective basis which is on power with current driven speakers. In addition there can be power supply problems when such speakers are used in remote locations.

OBJECT

It is an object of the present invention to overcome at least one of the abovementioned problems of prior art flat or planar loudspeakers or to at least provide the public with a useful choice.

SUMMARY OF THE INVENTION

In one aspect the invention resides in a loudspeaker including in combination a planar diaphragm which can be vibrated to radiate sound, the diaphragm having photovoltaic means adapted to convert light to electrical energy, a driver unit attached to the diaphragm in one or more selected positions, the driver unit caused by varying electric current to vibrate the diaphragm and whereby exposing the diaphragm to light also enables electricity to be generated.

Preferably the diaphragm is formed from a sheet material.

Preferably the sheet material is flexible but has internal stiffening means to prevent the diaphragm from collapsing from its own weight. Preferably the integral stiffening means comprises a cellular structure of the sheet material.

Where sheet material without a cellular structure is used, the stiffening means can include

ridges, swages or other stiffening sections moulded or attached to the diaphragm.

Preferably the sheet material is core flute or corrugated cardboard, however, other material

such as injection moulded or extruded plastic having a flat configuration may also be used.

Preferably the core flute or corrugated cardboard has a cellular structure comprising

longitudinal cells which have a square or substantially square cross section.

Preferably the diaphragm when formed from core flute or corrugated cardboard is between 3

and 8 millimetres thick and most preferably about 5 millimetres thick.

In an alternative version, the diaphragm can be constructed of a resilient plastic such as high- density polypropylene or equivalent material of uniform consistency and thickness.

In the alternative the diaphragm may be of non-uniform consistency or thickness in selected regions to improve or tune the loudspeaker's frequency response. The diaphragm may also have moulded regions of ribs, grooves or other patterns to improve or tune the loudspeaker^'s frequency response.

Suitably the diaphragm is rectangular, square or rounded square or oval shaped or any combination thereof.

Preferably the diaphragm is mounted on a brace or foot of stainless steel or other material.

Preferably the brace or foot supporting the diaphragm is of a sufficient weight to prevent

movement across a surface on which the brace or foot is placed when the speaker is operating. Preferably the brace or foot has pads or contact regions of friction material such as rubber to

further prevent movement across a surface when the speaker is in operation.

The diaphragm alternatively may be hung from a hanging mount in the manner of a picture. The diaphragm can also be pinned to a wall by mounting means located along the edges or

sides of the diaphragm.

Preferably there is a single driver unit however two or more driver units may be placed at

selected positions on the diaphragm to achieve a desired vibrational response of the

diaphragm.

Preferably the driver unit comprises a coil assembly which is non-linear in its electrical

response.

Preferably the weight of the driver unit is at least between 50 to 100 grams and ideally around 60 grams.

Preferably the magnet of the driver unit is a neodymium iron/boron sinter magnet selected for

its power and mass. Preferably the weight of the magnet is about 20 grams however heavier magnets can be used.

Preferably the driver unit is mounted by a damper sealer to the diaphragm.

Preferably the damper sealer is neoprene or rubber.

Preferably the driver unit is located off centre with respect to the diaphragm in order to improve the frequency response of the loudspeaker. In the alternative the driver unit can be mounted in a separate enclosure which is then

attached to the diaphragm in a quasi bi-planar configuration wherein the enclosures responds

to internal frequencies and transmits sounds to the rear of the diaphragm.

Preferably the quasi bi-planar enclosure should be distanced sufficiently away from the

diaphragm to create a non-ported sealed chamber.

Preferably a frame or peripheral chassis surrounds the diaphragm. Alternatively the frame or

chassis can comprise two or more frame members attached to the sides or edges of the

diaphragm.

Where the frame or chassis surrounds the diaphragm, there can also be attached to the frame

or chassis a quasi bi-planar rear panel which together with the diaphragm forms an enclosure

for the driver unit.

Preferably the rear panel is formed of sheet material which responds to the internal

frequencies of the enclosure so formed and vibrates to transmit sound away from the diaphragm. The panel may or may not have apertures to improve the acoustic performance

of the loudspeaker.

Preferably the frame or chassis is insulated from the diaphragm by means of a damper of foam or other suitable material.

In the alternative, the damper can comprise a combination of hard and soft materials to variably insulate the diaphragm from the frame or chassis.

In another version of the invention, the driver unit can be suspended from the frame or

chassis by means of a movable yoke attached to a frame, the yoke being substantially parallel to the diaphragm to allow the driver unit to transfer its momentum and inertial energy to the

diaphragm without the diaphragm actually supporting the weight of the driver unit.

Preferably the yoke is stainless steel wire, however other yokes of resilient plastic or

equivalent materials can be used.

Preferably the photovoltaic means comprises thin layer profile photoelectric cells covering an entire surface of the diaphragm.

Preferably there is a battery storage means adapted to store electricity produced by the photovoltaic means.

In another aspect, the invention resides in a loudspeaker substantially as herein before described with the inclusion of cordless means adapted to enable the loudspeaker to be operated without leads or wires from a current source.

Preferably the cordless means comprises a radio frequency signal receiver with complementary power amplification means to provide varying electric current to the driver unit corresponding to the signals received or operated by signals from an internally stored audio program source typically a tape. CD or hard disc storage device.

Suitably there is a complementary radio signal generation and transmission means to generate and transmit the signals received by the signal receiver. Suitably the signal generation and transmission means is coupled to an audio amplifier connected to a source of sound or music.

Preferably the cordless means is powered by current directly from the photovoltaic means and/or the battery storage means.

Preferably the cordless means and the battery storage means are housed in a housing or frame associated with the diaphragm. BRIEF DESCRIPTION OF THE DRAWINGS

In order to better understand the invention, reference will now be made to the accompanying drawings wherein.

Figure 1 is a perspective view of the invention according to Example 1, and

Figures 2a and 2b are transverse half sections of the preferred embodiment of the invention as described in Figure 1.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Referring now to Figure 1 of Example 1 , there is shown a loudspeaker 10 having a planar diaphragm 12 preferably of core flute or corrugated cardboard with a surface layer of thin photovoltaic film 14. This embodiment shows the diaphragm supported in an optional frame 16 or chassis. There is also shown a signal reception aerial 18 in the form of a loop located between the diaphragm 12 and the chassis 16.

Preferably associated with the chassis are an LED indicator 20 to show signal reception or that the power has been switched on. an on/off switch 22 and a fast charge socket 24 for connection to an external power supply to charge the storage battery (not shown).

Figures 2a and 2b show transverse half sections of the preferred embodiment of the loud speaker as described in Example 1.

Figure 2a to the left of centre line AA shows an assembly wherein the driver unit 26 is attached directly to the diaphragm 28 without a back wall or back panel. In relation to Figure 2a there is also shown an optional damper sealer 30 preferably of neoprene or soft rubber between the driver unit and the diaphragm.

In this arrangement the driver unit is preferably of a substantial enough mass to transfer its momentum and inertial energy to the diaphragm in order to extend the bass response of the diaphragm. The magnet 26a of the driver unit is preferably a neodymium iron-boron sinter circular magnet associated with a copper coil 32 which is attached to the diaphragm. The diaphragm is covered with a thin film photovoltaic layer 21 which is connected by a power lead 23 to a storage battery 25 which is preferably supported by the chassis 27.

There is also shown a radio signal receiver 29 to enable a cordless operation of the loudspeaker. In the alternative, the loudspeaker can be operated by signals from an internally stored audio program source e.g. a tape, CD or hard disc source.

Figure 2b to the right of centre line AA shows an alternative arrangement to Figure 2a with the addition of a back wall 34 which optionally supports the driver unit 36.

The back wall also forms an enclosure in the form a quasi bi-planar rear panel which may have ports 38 to extend the bass response of the loudspeaker.

ADVANTAGES

It will be evident that a major advantage of the present invention is the ability of the loudspeaker to also have a photoelectric capacity to generate electricity. The invention can be used in remote locations where power supply may be a problem and can be utilised as a solar panel for other applications apart from its functioning as a loudspeaker. Applications which could realise this advantage can include the use of the invention on sailing yachts or where information in remote locations such as forests or national parks can be provided via a solar powered system.

VARIATIONS

Finally, it will be appreciated that various other alterations and modifications may be made to the foregoing without departing from the scope of this invention as set forth in the appended claims.

Throughout the description and claims of this specification the word "comprise" and variations of that word, such as "comprises" and "comprising", are not intended to exclude other additives, components, integers or steps.

Claims

CLAIMS:

1. A loudspeaker including in combination a planar diaphragm which can be vibrated to radiate sound, the diaphragm having photovoltaic means adapted to convert light to electrical energy, a driver unit attached to the diaphragm in one or more selected positions, the driver unit caused by varying electric current to vibrate the diaphragm and whereby exposing the diaphragm to light also enables electricity to be generated.

2. A loudspeaker as claimed in claim 1 wherein the diaphragm is formed from a sheet material which is flexible and has internal stiffening means to prevent the diaphragm from collapsing from its own weight.

3. A loudspeaker as claimed in claim 2 wherein the stiffening means includes ridges,

swages or other stiffening sections moulded or attached to the diaphragm.

4. A loudspeaker as claimed in any one of the preceding claims wherein the integral

stiffening means comprises the cellular structure of the sheet material.

5. A loudspeaker as claimed in claim 4 wherein the sheet material is core flute or corrugated cardboard.

6. A loudspeaker as claimed in claim 5 wherein the core flute or corrugated cardboard has a

cellular structure comprising longitudinal cells which have a square or substantially

rectangular cross section.

7. A loudspeaker as claimed in any one of claims 1 to 3 wherein the diaphragm is constructed of a resilient plastic such as high-density polypropylene of uniform consistency and thickness.

8. A loudspeaker as claimed in claim 7 wherein the diaphragm is of non-uniform consistency or thickness in selected regions to improve or tune the loudspeaker^'s frequency response.

. A loudspeaker as claimed in claim 8 wherein the diaphragm also has moulded regions of ribs, grooves or other patterns to improve or tune the loudspeaker's frequency response.

10. A loudspeaker as claimed in any one of the preceding claims wherein the photovoltaic means comprises thin layer profile photoelectric cells covering an entire surface of the diaphragm.

1 1. A loudspeaker as claimed in claim 10 wherein there is battery storage means adapted to store electricity produced by the photovoltaic means.

12. A loudspeaker as claimed in any one of the preceding claims wherein there is inclusion of cordless means adapted to enable the loudspeaker to be operated without leads or wires from a current source.

13. A loudspeaker as claimed in claim 12 wherein the loudspeaker is operated by signals from an internally stored audio program source.

14. A loudspeaker as claimed in claim 12 wherein the cordless means includes a radio frequency signal receiver with complementary power amplification means to provide varying electric current to the driver unit corresponding to the signals received.

15. A loudspeaker as claimed in claim 14 wherein the cordless means includes a complementary radio signal generation and transmission means to generate and transmit the signals received by the signal receiver and the signal generation and transmission means is cbupled to an audio amplifier connected to a source of sound or music.

16. A loudspeaker as claimed in claim 15 wherein the cordless means is powered by current directly from the photovoltaic means and/or the battery storage means.

17. A loudspeaker as claimed in claim 16 wherein the cordless means and the battery storage means are housed in a housing or frame associated with the diaphragm.

18. A loudspeaker substantially as herein described with reference to the accompanying drawings.