WO2003073785A1

WO2003073785A1 - Flat loudspeaker for the whole acoustical frequention spectrum

Info

Publication number: WO2003073785A1
Application number: PCT/NL2003/000142
Authority: WO
Inventors: Jacobus Maria De Rooij
Original assignee: Jacobus Maria De Rooij
Priority date: 2002-02-26
Filing date: 2003-02-21
Publication date: 2003-09-04
Also published as: NL1020060C1; EP1479262A1; AU2003214714A1

Abstract

The present invention concerns a loudspeaker (100, 101, 102) which is constructed of a combination of a passive and/or several active oscillation systems (4, 5, 4', 5', 13, 5'', 6, 7, 6', 7', 7'' and 14) for several frequency bands of the sound spectrum, in which each of the active oscillation systems (4, 5, 4', 5', 13, 5'', 6, 7, 6', 7', 7'' and 14) is composed of a coil (4, 5, 4', 5', 13 and 5'') which is coupled to a ddiaphragm (6, 7, 6', 7' 7'' and 14), in which at least one of these active oscillation systems (4, 5, 4', 5', 13, 5'', 6, 7, 6', 7', 7'' and 14) is mounted within the circumference of a ring magnet (2, 2a, 2b, 2c, 2' and 2''), whether or not with exclusion of the inner edge, all parts of at least one of these passive oscillation systems (4, 5, 4', 5' 13, 5'', 6, 7, 6', 7', 7'' and 14) are situated outside the circumference of the ring magnet (2, 2a, 2b, 2c, 2' and 2'').

Description

FLAT LOUDSPEAKER FOR THE WHOLE ACOUSTIC FREQUENCY SPECTRUM

The present invention relates to a loudspeaker that is constructed of a combination of a passive and/or several active oscillation systems for several frequency bands of the sound spectrum. Each active oscillation system is composed of a coil coupled to a diaphragm. At least one of these active oscillation systems is mounted within the circumference of a ring magnet. Whether or not with exclusion of the inner edge, all parts of at least one of these passive oscillation systems are situated outside the circumference of the ring magnet. The diaphragms can be flat, tapered and, for example, be folded-in as meant in figures 1 up to 3. With an active oscillation system a diaphragm is coupled to a coil. A passive oscillation system is a diaphragm, that can possibly be coupled to a coil but not necessarily. After all, a passive oscillation system is operated by another medium than electric power. For example by pressure differences in the air.

Many known loudspeaker systems aim. to improve the sound reproduction by using more coils, in which one aims for improvement of the sound quality and/or efficiency. Many of the known systems are meant to improve the sound quality of small sound reproduction systems for mobile phones or earphones, in which several coils are coupled to one diaphragm. The aim of the present invention concerns to provide such a loudspeaker which can reproduce all frequencies from one central axis and can give pulse amplifications through which a natural sound can be reproduced, by separated oscillation systems.

An additional advantage is the flatness of the loudspeaker which can be realized by a folded-in cone or by leaving out the top of the cone and mounting it within the circumference of the ring magnet. All oscillation systems can be separated mechanically and coupled acoustically. Also, for example, according to figures 1 up to 3, the oscillating systems can be coupled mechanically and acoustically.

The preferred construction of the invention will be described by way of example, and with reference to the accompanying drawing. In which: Fig. 1 shows a cross-section of a loudspeaker with two oscillation systems; Fig. 2 shows a cross-section of a loudspeaker with three oscillation systems; and Fig. 3 finally shows a cross-section of a loudspeaker with three oscillation systems and a narrow ring magnet.

Figure 1 shows a cross-section of a loudspeaker with two oscillation systems. The frame 1 of the loudspeaker carries a ring magnet 2 that is constructed of two ring magnets 2a and 2b and in between a soft-iron ring 2c, with a hole 3 in the ring magnet 2 and in which the two magnets 2a and 2b, for example, with the same polarity are applied against the intermediate soft-iron ring 2c. Also the ring magnet 2 can be constructed as a system in which, for example, one magnet is used and is enclosed by soft iron in order to create a closed magnetic system. The outside of the ring magnet 2 is enclosed by a coil 4 and connected on the inner side of the hole 3 of the ring magnet 2 is situated coil 5. Coils 4 and/or 5 are meant for the active oscillation system and can be operated independently. When a passive oscillation system is used, possibly coils 4 and/or 5 can be left out. Coil 4 is coupled to the most outer diaphragm 6 and the most inner coil 5 is coupled to the diaphragm 7. Diaphragm 6 is coupled to the frame 1 on the outer edge by means of a flexible membrane 8 and the outer edge of the diaphragm 7 is coupled to the inner edge of the most outer diaphragm ring 6 by means of a flexible membrane 9. Coils 4 and 5 are mounted to the bottom side of coils 4 and 5 by means of the flexible membranes 10 and 11. These flexible membranes 10 and 11 are not necessarily needed and can also be mounted differently, for example directly on the diaphragms 6, 7, 6^r , 1 ' , 1" and 14. In figures 2 and 3 corresponding parts are indicated with accent marks. The diaphragms 6 and 7, according to figures 1 up to 3, are flat diaphragms which can be considered as self-folded-in cones.

Figure 2 shows a cross-section of a loudspeaker in which in hole 3' of the ring magnet 2' another extra magnet system 12 is set up on the frame 1' which is enclosed by a coil 13 and which is coupled to a small central diaphragm 14 which is coupled to the outer edge with a flexible membrane 15 to the inner edge of the diaphragm 1 ' with coil 5^r, which diaphragm 1' , in its turn is coupled to the outer edge with a flexible membrane 16 to the inner edge of the most outer diaphragm 6' with coil 4' .

Finally, figure 3 shows another variant in which a narrow embodiment of the ring magnet 2" is used so that a larger hole 3" is created, which improves the sound quality.

Finally it has to be emphasized, that the figures and the above description of the loudspeakers constitute a preferred embodiment of the present invention and that further variations and modifications are still possible without departing the scope of this patent description. Also the measurements can vary in many ways . The configuration of the diaphragms, for example, can vary in thickness, choices in material such as paper, polypropylene, titanium, carbon fibre, aluminium, magnesium and such and shape such as folded-in cone, conventional cone or, for example, a cone with a corner folded back. The number of angles can be enlarged or limited as well as the angle degrees .

The invention, in this case the loudspeaker can be used in many situations, such as in ceilings, cars, telephones and audio equipment without departing the scope of this patent description.

Claims

1. Flat loudspeaker for the whole acoustic frequency spectrum, characterized in that, the loudspeaker, according to figures 1, 2 and 3, is constructed of a combination of a passive and/or several active oscillation systems (4, 5, 4', 5', 13, 5", 6, 7, 6', 1 ' , 1" and 14) in which each active oscillation system (4, 5, 4', 5' , 13, 5", 6, 7, 6^f , 7', 7" and 14) is composed of a diaphragm (6, 7, 6', 7', 7" and 14) and coupled to that a coil (4, 5, 4', 5', 13 and 5") , in which at least one of these active oscillation systems (4, 5, 4', 5', 13, 5", 6, 7, 6' , 7', 7" and 14) is mounted within the circumference of the ring magnet (2, 2a, 2b, 2c, 2 ' and 2") , whether or not with exclusion of the inner edge, all parts of at least one of these passive oscillation systems (4, 5, 4', 5', 13, 5", 6, 7, 6', 7', 1" and 14) are situated outside the circumference of the ring magnet (2, 2a, 2b, 2c, 2' and 2") . 2. Flat loudspeaker as claimed in claim 1, characterized in that, the loudspeaker, according to figures 1, 2 and 3, is constructed of several active oscillation systems (4, 5, 4', 5', 13, 5", 6, 7, 6^f , 7', 7" and 14), in which each oscillation system (4, 5, 4 , 5', 13, 5", 6, 7, β , 1 ' , 1" and 14) is composed of a diaphragm (6, 7, 6', 7', 7" and 14) and coupled to that a coil (4, 5, 4', 5^r , 13 and 5"), in which at least one of these active oscillation systems (4, 5, 4', 5', 13, 5", 6, 7, 6', 1 ' , 7" and 14) is mounted within the circumference of the ring magnet (2, 2a, 2b, 2c, 2 ' and 2") , whether or not with exclusion of the inner edge, all parts of at least one of these passive oscillation systems (4, 5, 4', 5' , 13, 5", 6, 7, 6', 1 ' , 7" and 14) are situated outside the circumference of the ring magnet (2, 2a, 2b, 2c,

2 ' and 2") .

3. Flat loudspeaker as claimed in claim 1, characterized in that, the loudspeaker, according to figures 1, 2 and 3, is constructed of a combination of passive and active oscillation systems (4, 5, A ' , 5', 13, 5", 6, 7, 6', 7', 7" and 14), in which the active oscillation system (4, 5, 4', 5', 13, 5", 6, 7, 6', 7', 7 1'" and 14) is composed of a diaphragm (6, 7, 6', 7', 1" and 14) and coupled to that a coil (4, 5, 4', 5' , 13 and 5"), whether or not with exclusion of the inner edge, all parts of the passive oscillation system (4, 5, 4', 5' , 13, 5", 6, 7, 6' , l ^r , 1" and 14) are situated outside the circumference of the ring magnet (2, 2a, 2b, 2c, 2 ' and 2 ") .