WO2001022774A1

WO2001022774A1 - Loudspeaker

Info

Publication number: WO2001022774A1
Application number: PCT/NZ2000/000177
Authority: WO
Inventors: Christopher Colin Lock; John Frederick Corey; Graeme Oliver Jones; Kelly Charles Waterman
Original assignee: Slab Technology Limited
Priority date: 1999-09-24
Filing date: 2000-09-08
Publication date: 2001-03-29
Also published as: AU7462200A

Abstract

A low profile loudspeaker having a flat or planar diaphragm contiguous with and utilising the material of a vehicle's internal lining as the diaphragm. The loudspeaker also in some applications uses a body cavity of the vehicle such as a door cavity as a bass chamber.

Description

Title: LOUDSPEAKER

FIELD

This invention relates to a loudspeaker in particular but not limited to a loudspeaker having a planar diaphragm adapted for confined space and vehicular applications.

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 electrostatic 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 par with cone driven speakers. Most of these prior art flat speakers have also not

been readily adaptable to automotive, marine, aviation or portable applications where space

is at a premium.

OBJECT

It is an object of the present invention to overcome at least one of the above mentioned 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, the diaphragm formed as a contiguous portion of an internal surface of a passenger compartment of a vehicle, 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 whereby sound is produced.

Preferably the diaphragm is formed from part of the dashboard, parcel shelf or door or cabin lining of a vehicle. Alternatively, the diaphragm may be of another material which is

contiguous with the material of the dashboard, parcel shelf or door or cabin lining.

Preferably the material used for the internal surface and also the diaphragm is a plastic which

is selected from a group of plastics normally used for the interiors of passenger vehicles and

which exhibit good ultraviolet tolerance and ability to withstand high temperatures.

Preferably the diaphragm which is normally of a thinner cross section to the rest of the

interior surface or lining has integral stiffening means.

Preferably the integral stiffening means comprises ridges, swages or other stiffening sections moulded or attached to the diaphragm.

Suitably a diaphragm can also be covered with a protective mesh or cloth or have a moulded crinkled or textured surface.

The diaphragm when formed as part of a dashboard, parcel shelf or door panel may or may not have a true or a mock foraminous configuration to indicate that it is a loudspeaker. Preferably the diaphragm has integrally moulded mounting means to mount the driver unit.

The mounting means may or may not comprise a yoke to support the driver unit. Where a

yoke is absent, the driver unit can optionally be fastened directly to the diaphragm by means of adhesive or other suitable fastening means.

Preferably where there is a body cavity, typically a door cavity, behind the diaphragm, the

driver unit can be mounted on the diaphragm external to the cavity and facing backwards into

the cavity, the cavity forming a bass chamber, and wherein the sound is projected by the diaphragm into the passenger compartment or cabin.

Preferably the diaphragm and/or the body cavity may have ports to improve or optimise the

bass response of the loudspeaker.

Where the driver unit is mounted on a yoke, the yoke can either be a concave or convex

structure projecting into the cavity for mounting the driver unit so that the diaphragm is substantially mounted flush with the interior surface.

Where the driver unit is mounted directly on the diaphragm there could also be a mounting

for a dome high range radiator on the outward-facing base of the magnet of the driver unit to transmit high frequencies.

In the alternative the dome high range radiator can be mounted directly on a protective mesh of the loudspeaker. Preferably there is a single driver unit, however, two or more driver units may be placed in 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 and 100 grams and ideally 60

Where the driver unit is fastened directly to the diaphragm without a yoke, preferably the driver unit is of a heavier weight or sufficient mass to transfer its momentum and/or inertial

energy to the diaphragm to extend the frequency response of the diaphragm when operating.

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 such as where the driver unit is mounted directly to the diaphragm.

Preferably the driver unit has a damper sealer connected 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 enclosure 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.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that this invention may be more readily understood and put into practical effect, reference will^ now be made to the accompanying drawings which illustrate one or more

preferred embodiments of the invention and wherein:

Figure 1 : is a side view of the loud speaker according to Example 1.

Figure 2a and 2b: are half sectional views of a further embodiment according to Example 2.

Figures 3a and 3b: are half sectional views of a further embodiment according to Example 3.

Figure 4a: is a perspective view of one application according to Example 4,

Figure 4b: is a side view and partial exploded view of the application shown in Figure 4a.

Figures 5a-5f: are half sectional views of further embodiments according to Example 5. DETAILED DESCRIPTION OF THE INVENTION

Example 1

Figure 1 shows a side view of the loudspeaker 10 according to Example 1. The loudspeaker preferably comprises a diaphragm 12 of a thin plastics material of between 2 and 5

millimetres thick and most preferably 2.5 millimetres thick. The diaphragm is shown supported by a ledge 14 in the doorframe 16 however a flush mounting is also possible. There is preferably a spacer 18 or gasket 18 holding the diaphragm by means of screws 19,

20 such as self-tapping screws which can be overlaid by the upholstery 22 of the door. In

this version, there is preferably a mesh 24 to protect the driver unit 26 which is mounted on the diaphragm 12 projecting into the passenger compartment of the vehicle (not shown).

There can also be included an optional high range dome radiator 28 mounted on top of the magnet case of the driver unit 26 to transmit high frequencies. The door cavity conveniently 30 forms a bass chamber for the loudspeaker. Preferably the door cavity is air tight to avoid

moisture problems from condensation which could affect the performance of the

loudspeaker. The sealing of the bass chamber cavity is also important in order to optimise

the acoustic performance of the loudspeaker. The driver unit 26 is preferably comprised of a

neodymium iron/boron sinter circular magnet 32 having an electrically non-linear coil 34 of copper wire or aluminium strip wire. The driver unit preferably has a neoprene or soft rubber damper sealer 36. The coil is preferably fixed by adhesive directly to the diaphragm or may impact the diaphragm through a button (not shown) or other intermediary member. Preferably the driver unit is connected by copper strips 38 glued to the diaphragm which are in turn attached to wires (not shown) leading to the current source of an amplifier (not shown). Preferably the total weight of the driver unit is around 60 grams. The weight of the magnet is preferably between 12 grams and 20 grams so that the inertial energy of the magnet when excited by electrical current from the amplifier (not shown) is transferred directly to the diaphragm. Wires supplying the driver unit with electric current may either be attached to

copper strips leading to the coil which are glued to the diaphragm or can exit the loudspeaker

around the magnet (not shown).

Example 2

Figure 2 shows a loudspeaker according to Example 2 as Figures 2a and 2b shown on either

side of centreline AA. Figure 2a to the left of centreline AA shows the driver unit 52

mounted inside the door cavity 54. In this example, the driver unit is an optional "full floating^" version wherein the driver unit is attached to the diaphragm 56 by means of the

damper sealer 58 without the support of a yoke. Power to the driver unit is shown by copper strips 60 attached preferably by adhesive to the diaphragm which are in turn attached to wires (not shown) leading to a current source such as an amplifier (not shown).

Figure 2b. to the right of centreline AA. shows the driver unit 70 mounted inside the door

cavity 72 with the aid of a yoke 74. The yoke is shown attached to the doorframe by means of self- tapping screws 78. In an alternative version the yoke may be formed as part doorframe 76 wherein the driver unit and diaphragm 79 are separate attachments. There is

also shown an optional speaker mesh 80 which is mainly for aesthetic reasons as the driver

unit is not exposed by being located behind the diaphragm 79. The door cavity 72 forms a bass chamber for the speaker. There is also shown a damper sealer 84 preferably of neoprene or rubber between the driver unit and the diaphragm. Example 3

Figure 3a and 3b of Example 3 shows the loudspeaker 90 which can be mounted directly to an internal panel or a door panel or a dashboard 92 of a vehicle. The dashboard can or may not have a back wall as shown by Figure 3b. The diaphragm 95 may be integrally formed from the plastic of the door panel or dashboard or may be bonded to inner layers 93 of the

dashboard or door panel surface. The driver unit 94 may have a damper sealer 96. The driver unit is shown in direct contact with a back wall 98 of the panel surface which may or

may not have ports 100 designed to provide a bass reflex performance of the loudspeaker.

Example 4

Figure 4a of Example 4 shows a vehicle rear parcel shelf mounting 102 for a speaker (not shown) having a perforated mesh cover 104. The mesh may be of a triangular 106 or other

configuration such as when the speaker is placed in a corner of the parcel shelf. A yoke 108

to support the driver unit (not shown) can be formed from the metal or plastic of the parcel shelf.

Figure 4b shows a side and partially exploded view of the rear parcel shelf of Figure 4a wherein the driver unit 1 10 can be directly bonded to the yoke 112 and the diaphragm 114

bonded in turn to the driver unit and to the surface of the shelf 116. There may be optional

diaphragm covers of different configurations 118, 120, 122 in the form of vinyl with pre-cut holes, mesh or cloth, laminate or alternatively, the parcel shelf cloth covering may be used to hide the diaphragm. Example 5

Figures 5a to 5f shows various partial half sectional views of the preferred methods of

constructing the loudspeaker according to Example 5 wherein the diaphragm is contiguous with the interior surface lining of a vehicle. Figure 5a to the left of centreline CC shows a planar diaphragm 130 as a separate member to the interior surface lining 132. In this version

there is also shown a back wall 134 forming an enclosure 136 behind the driver unit 138

which also has a mounting portion 140 to support the driver unit. The enclosure forms a small bass chamber for the loudspeaker and may or may not be ported (not shown). The

diaphragm 130 is shown with an optional cloth cover 142 which wraps over the diaphragm

and is secured in place by toothed portions 144 of the internal lining.

Figure 5d to the right of centreline CC shows a diaphragm 150 which is contiguous with the

surface lining 152 and which also has a cloth covering 154. The cloth covering is secured by the toothed portions 156 of the surface lining 158. In this version there is no back wall to form an enclosure. The magnet 160 of the driver unit 162 is suspended by a damper sealer

164 to the diaphragm while the coil 166 is attached preferably by adhesive to the diaphragm. The mass of the magnet is preferably substantial enough to transfer its momentum and

inertial energy to the diaphragm to produce an extended bass response of the loudspeaker.

Figures 5c and 5d show views corresponding to Figures 5a and 5b, respectively. The main difference in this embodiment is the use of a continuous cloth covering 170, 171 to cover the diaphragm 172. 173 and the surrounding internal surface lining. The diaphragm is shown preferably abutting the surface lining 174, 175 to avoid any gaps between the diaphragm and the lining. It will be evident that a speaker can be subtly hidden from view in this version. Figures 5e and 5f show views corresponding to Figures 5c and 5d, respectively. In this version, the diaphragm 180, 181 is of the same plastics material as the rest of the surrounding

structure 182, 183. The diaphragm preferably has moulded ridges 184, 186 to tune the vibrational response of the diaphragm to the driver unit 188, 189. As with Figures 5c and 5d there is shown an optional cloth covering 190, 191 to completely camouflage the

loudspeaker.

In all the above versions, the diaphragm can also have a perforated or foraminous

configuration to allow diaphragm to also "breathe" if required.

ADVANTAGES OF THE PREFERRED EMBODIMENT

The advantages of the preferred embodiment include the fact that the diaphragm of the

loudspeaker can be incorporated into the design and structure of the interior linings of passenger compartments or cabins of vehicles. This is an advantage where space and cost are significant factors in the design of sound systems for such vehicles. In addition, versions where a driver unit may be attached directly to the diaphragm by means of adhesive or otherwise without the necessity of a supporting yoke are also simpler to construct and must

contribute to a saving in manufacturing and assembly line costs.

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, the diaphragm formed as a contiguous^ portion of an internal surface of a passenger compartment of a vehicle, 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 whereby sound is produced.

2. A loudspeaker as claimed in claim 1 wherein the diaphragm is formed from part of a dashboard, parcel shelf or door or cabin lining of the vehicle.

3. A loudspeaker as claimed in claim 1 wherein the diaphragm is of another material which is contiguous with the material of the dashboard, parcel shelf or door or cabin lining of the vehicle.

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

a thinner cross section to the rest of the interior surface or lining and has integral stiffening means.

5. A loudspeaker as claimed in claim 4 wherein the integral stiffening means comprises ridges, swages or other stiffening sections moulded or attached to the diaphragm.

6. A loudspeaker as claimed in any one of the preceding claims wherein the diaphragm is covered with a protective mesh or cloth or has a moulded crinkled or textured surface.

7. A loudspeaker as claimed in any one of the preceding claims wherein the diaphragm when formed as part of a dashboard, parcel shelf or door panel has a true or a mock foraminous configuration to indicate that it is a loudspeaker.

8. A loudspeaker as claimed in any one of the preceding claims wherein the diaphragm has integrally moulded mounting means to mount the driver unit.

9. A loudspeaker as claimed in any one of the preceding claims wherein the driver unit is fastened directly to the diaphragm by means of adhesive or other suitable fastening

means.

10. A loudspeaker as claimed in any one of the preceding claims for installation where there is a body cavity behind the diaphragm, wherein the driver unit is mounted on the diaphragm external to the cavity and facing backwards into the cavity, the cavity forming a bass chamber, and sound is projected by the diaphragm into the passenger compartment or cabin.

1 1. A loudspeaker as claimed in claim 10 wherein the diaphragm or the body cavity is ported

to improve or optimise bass response of the loudspeaker.

12. A loudspeaker as claimed in any one of the preceding claims wherein the driver unit is mounted in a separate enclosure which is attached to the diaphragm in a quasi bi-planar configuration wherein the enclosure responds to internal frequencies and transmits sounds to the rear of the diaphragm.

13. A loudspeaker as claimed in claim 12 wherein the quasi bi-planar enclosure is distanced sufficiently away from the diaphragm to create a non-ported sealed chamber.