WO2013100863A2

WO2013100863A2 - Coaxial diaphragm loudspeaker unit and mirror coaxial diaphragm speaker

Info

Publication number: WO2013100863A2
Application number: PCT/SG2013/000072
Authority: WO
Inventors: Shihuang Li
Original assignee: Shihuang Li
Priority date: 2011-12-31
Filing date: 2013-02-22
Publication date: 2013-07-04
Also published as: WO2013100863A3

Abstract

This invention discloses a kind of coaxial diaphragm loudspeaker unit that includes an electromagnetic loudspeaker. This electromagnetic loudspeaker includes a cone that is driven by a voice coil and a cone frame to secure the cone; a characteristic is its additional inclusion of a passive diaphragm; the said passive diaphragm is secured on the said cone frame using elastic components. It is coaxial with the said cone and has a ring-shaped circumference distributed outside it; at the same time, one side of the said passive diaphragm has a sealed connection to the air of one side of the said cone; the other side of the said passive diaphragm and the other side of the said cone are both exposed to the open space. These coaxial passive diaphragm and cone have uniform vibration with the air in the resonant cavity. This vibration is virtually unaffected by the internal geometric structure of the sealing cap. The coloration is also low so there need not be too many restrictions for the design of the sealing cap. It is only necessary to ensure sufficient sealing; the plan for the entire loudspeaker unit is simple and reliable, and it has good applicability.

Description

Coaxial Diaphragm Loudspeaker Unit

and Mirror Coaxial Diaphragm Speaker

Technical Field

This invention involves fittings from the electric-acoustic conversion field. Specifically, it involves a loudspeaker unit with coaxial diaphragm and a coaxial diaphragm speaker that utilizes the aforementioned loudspeaker unit.

Background Technology

In the electric-acoustic conversion field, an electromagnetic loudspeaker generally achieves electric-acoustic conversion by using an electrified coil in a magnetic field to drive cone vibration. This is done with both sides of the cone exposed to the open space. Usually, the frequency response for a single electromagnetic loudspeaker is very weak at medium and low frequencies due to the dimensions of the cone being almost negligible compared with the wavelengths of the sound waves at medium and low frequencies. This causes the sound wave outputs of the two opposite phases to cancel out during cone vibration, and it is thus impossible to emit sounds with enough power at medium and low frequencies. In order to achieve the objective of sufficiently restoring the sounds at medium and low frequencies, it is usually necessary to place the loudspeaker unit in a specially designed speaker to avoid the phase cancellation of sound waves. An excellent restoration effect can then be achieved.

On the one hand, the speaker's design is very important because the dimensions of its internal structure have a very big impact on the phase inversion effect. For the same loudspeaker, any volume deviation for the application site will have a large impact on the output sound quality. Should the dimensions of the speaker body be inappropriately designed, it is easy to cause unwanted coloration; on the other hand, in order for the speaker to fulfill its function of achieving adequate sound quality, it is difficult to reduce its size. This causes much inconvenience for the application sites of the speaker.

Invention Content

In view of the difficulty in changing the dimensions of a speaker matched with a loudspeaker based on the usual plan mentioned above which also makes design customization tedious, this invention proposes a kind of coaxial diaphragm loudspeaker unit and a coaxial diaphragm speaker that utilizes the aforementioned loudspeaker unit. The technical plan is as follows: The coaxial diaphragm loudspeaker unit includes an electromagnetic loudspeaker. This electromagnetic loudspeaker includes a cone that is driven by a voice coil and a cone frame to secure the cone; it also includes an additional passive diaphragm; the said passive diaphragm is secured on the said cone frame using elastic components. It is coaxial with the said cone and has a ring-shaped circumference distributed outside it; at the same time, one side of the said passive diaphragm has a sealed connection to the air of one side of the said cone; the other side of the said passive diaphragm and the other side of the said cone are both exposed to the open space.

Below are several preferred improvements for this technical plan:

In a preferred embodiment, the said cone and the said passive diaphragm are both rotationally symmetric.

In a preferred embodiment, the said passive diaphragm has a flat form.

In a preferred embodiment, the radius of the said passive diaphragm gradually decreases along its axial direction.

In a preferred embodiment, one side of the said passive diaphragm has a sealed connection to the front air of the said cone.

In a preferred embodiment, one side of the said passive diaphragm has a sealed connection to the rear air of the said cone.

The above is the plan for the coaxial diaphragm loudspeaker unit. Should this type of loudspeaker unit be used, it can be matched with the following speaker plan:

The mirror coaxial diaphragm speaker includes two loudspeakers that are situated axially opposite to mirror each other. The pair is secured on a cone frame; also, the coaxial passive diaphragm has a ring-shaped circumference distributed coaxially at the periphery of the cone of the said loudspeaker. It is secured on the said cone frame using elastic components, and this setup is correspondingly mirrored for every said loudspeaker; further, the same side of the said coaxial passive diaphragm and the same side of the said cone are connected to one part of the said cone frame to jointly form a sealed resonant cavity; the other side of the said coaxial passive diaphragm and the other side of the said cone are jointly exposed to the open space.

There are several preferred embodiments for this mirror coaxial diaphragm speaker which can be reflected in the following areas:

In a preferred embodiment, a characteristic of the said mirror coaxial diaphragm speaker is that the cone front of the said loudspeaker is located in the said resonant cavity. In a preferred embodiment, the cone rear of the said loudspeaker is located in the said resonant cavity.

In a preferred embodiment, the said coaxial passive diaphragm has a flat form.

In a preferred embodiment, the radius of the said coaxial passive diaphragm gradually decreases along its axial direction.

In a preferred embodiment, the cone and passive diaphragm of the said loudspeaker are rotationally symmetric.

The beneficial effects of the technical plan for the loudspeaker unit and speaker are:

1. The coaxial passive diaphragm and cone have uniform vibration with the air in the resonant cavity. This vibration is virtually unaffected by the internal geometric structure of the sealing cap. The coloration is also low so there need not be too many restrictions for the design of the sealing cap. It is only necessary to ensure sufficient sealing; the plan for the entire loudspeaker unit is simple and reliable, and it has good applicability.

2. When the loudspeaker cone is driven to vibrate, the air in the resonant cavity as well as the passive diaphragm will become its rear loads and drive it to vibrate. The passive diaphragm and cone front will then output in the same phase, and this eliminates the acoustic short circuit between the front and rear of the cone. This allows very good restoration output for the sound, particularly at medium and low frequencies.

3. For the mirror diaphragm speaker, when the loudspeaker is driven by the same audio signal, the axial offset for the kinetic energy of its vibration in the entire device allows the cone frame to avoid excessive coloration during operation from the additional vibration of the extra parts. There will also not be too much additional vibration for the device they are housed in.

4. The passive diaphragm uses its gradually decreasing radius along the axial direction to make its vibration more balanced in the axial direction. Therefore, the vibration of the passive diaphragm and its mirror is more stable, and the coloration of the speaker is lower.

Description of Attached Diagrams

The following diagrams provide further description for the embodiments of this invention: Figure 1 is the sectional schematic diagram for embodiment 1 of this invention;

Figure 2 is the front view diagram for the embodiment in Figure 1 ;

Figure 3 is the sectional schematic diagram for the speaker in embodiment 2 of this invention;

Figure 4 is the front view diagram for the embodiment in Figure 3;

Figure 5 is the front view diagram for embodiment 3 of this invention;

Figure 6 is the sectional schematic diagram for embodiment 4 of this invention;

Figure 7 is the sectional schematic diagram for embodiment 5 of this invention;

Figure 8 is the front view diagram for the embodiment shown in Figure

7.

Description of Preferred Embodiments

Embodiment 1 :

As per Figure 1 , the sectional schematic diagram for embodiment 1 of this invention; Figure 2 is the front view diagram for the embodiment in Figure 1 ; the following explanation is with reference to these two diagrams:

This embodiment 1 is a coaxial diaphragm loudspeaker unit which includes a cone frame 10. This cone frame 10 has a circular contour that is rotationally symmetric. Its center part is an electromagnetic loudspeaker that has a complete cone 11. By means of cone hole 12, the front of this cone 11 is exposed to the open space; a flat annular passive diaphragm 13 is at the periphery of cone 11. While allowing vibration, this passive diaphragm 13 is secured on cone frame 10 using elastic components which are respectively inner elastic ring 14 and outer elastic ring 15. At the same time, passive diaphragm 13 is coaxial with cone 11. They are both circular and rotationally symmetric.

There is a sealing cap 16 on cone frame 10 relative to passive diaphragm 13 and the rear of cone 11. Together with passive diaphragm 13, cone 11 of the loudspeaker, inner elastic ring 14, outer elastic ring 15 and part of cone frame 10, this sealing cap 16 forms a sealed resonant cavity with air inside. Therefore, one side of passive diaphragm 13 and the back of cone 11 jointly have a sealed connection to this resonant cavity 17. At the same time, the other side of passive diaphragm 13 and the front of cone 11 are oriented toward the open space in the direction indicated by the arrow. In this way, when cone 11 of the loudspeaker is driven to vibrate, the air in resonant cavity 17 as well as passive diaphragm 13 will become its rear loads and drive it to vibrate. Passive diaphragm 13 and the front of cone 11 will then output in the same phase. This eliminates the acoustic short circuit between the front and rear of cone 11. This allows very good restoration output for the sound, particularly at medium and low frequencies; in addition, the coaxial passive diaphragm 13 and cone 11 have uniform vibration with the air in resonant cavity 17. This vibration is virtually unaffected by the internal geometric structure of sealing cap 16. The coloration is also low so there need not be too many restrictions for the design of the sealing cap. It is only necessary to ensure sufficient sealing; the plan for the entire loudspeaker unit is simple and reliable, and it has good applicability.

Embodiment 2:

As per Figure 3, the sectional schematic diagram for the speaker in embodiment 2 of this invention; Figure 4 is the front view diagram for the embodiment in Figure 3; the following explanation for embodiment 2 of this invention is with reference to these two diagrams:

Cone frame 10 is a rotationally symmetric component with mirror symmetry in the axial direction. Similar to embodiment 1 , a loudspeaker is secured in the center and the front of cone 11 is oriented toward the outside by means of cone hole 12. Passive diaphragm 13 is at the periphery of cone 11 of the loudspeaker. It is similarly secured on the cone frame using inner elastic ring 14 and outer elastic ring 15. Unlike embodiment 1 , the entire device is in the axial direction of cone 11 and passive diaphragm 13, and there are mirror units at its rear such as mirror passive diaphragm 13', mirror loudspeaker cone 11' and mirror cone hole 12'; sealing ring 18 is secured at the outermost periphery of cone frame 10. At the same time, together with passive diaphragm 13, cone 11 , inner elastic ring 14, outer elastic ring 15 and the abovementioned mirror units, this sealing ring forms resonant cavity 17. The entire device is a mirror coaxial diaphragm speaker. Besides having the advantages of the loudspeaker unit in embodiment 1 , this embodiment also has its unique value: When the loudspeaker is driven by the same audio signal, the kinetic energy of the respective corresponding vibration of cone 11 and mirror cone 11', as well as passive diaphragm 13 and mirror passive diaphragm 13', can all cancel out in the axial direction. For cone frame 10 and sealing ring 18, this avoids excessive coloration during operation from the additional vibration of the extra parts. There will also not be too much additional vibration for the device they are housed in; on the other hand, relative to sealing ring 18 and cone frame 10, the cone and diaphragm occupy most of the vibration plane for the device in reality. This causes the vibration area for coloration to be strictly limited which further reduces excess noise; at the same time, the width of sealing ring 18 can be constrained solely by the effective thickness of cone 11. The thickness of the entire speaker i.e. the width of sealing ring 18 can be made very small. This makes it suitable for molded flat type speakers and it is thus very universal.

Embodiment 3:

As per Figure 5, the front view diagram for embodiment 3 of this invention; the sectional schematic diagram for embodiment 3 is basically the same as that for embodiment 2 shown in Figure 3. The difference is that both the outer contour of sealing ring 18 and the shape of passive diaphragm 13 are square. A speaker of this shape has a very big advantage: It can form an array system in many combinations in the horizontal direction. Should the array resonate in a different low frequency band, not only can the entire resulting speaker array be small, it can also simultaneously possess excellent sound restoration capability.

Embodiment 4:

As per Figure 6, the sectional schematic diagram for embodiment 4 of this invention; the sectional layout for this embodiment is actually similar to that of embodiment 2 shown in Figure 3. The difference is that passive diaphragm 13 and its mirror 13' no longer have flat forms. Instead, their radii gradually decrease along their axial directions. Further, talking solely about the mirror, its large ends are mutually close and its small ends are mutually far. This results in a horizontal flat olive shape for resonant cavity 17. With such a form, when passive diaphragm 13 and mirror passive diaphragm 13' resonate due to the air in resonant cavity 17, besides withstanding pressure in the x direction, there are also horizontal forces all along the y direction perpendicular to x and using the axis as center. This causes the vibration of the diaphragm to be more balanced in the x direction. The vibration of passive diaphragm 13 and its mirror 13' also becomes more stable, and the coloration becomes lower; therefore, the hook on cone frame 10 can even be used to hang up the speaker without requiring any additional anti-vibration measures. This kind of securing method has even better sound restoration capability and also unique aesthetic value. Embodiment 5:

As per Figure 7, the sectional schematic diagram for embodiment 5 of this invention; Figure 8 is the front view diagram for the embodiment shown in Figure 7. The following explanation for embodiment 5 is with reference to these two diagrams:

Like the other abovementioned embodiments 2 to 4 of the speaker, this embodiment 5 similarly uses a flat ring shape for passive diaphragm 13 and its mirror 13'. Its biggest difference is the load method for loudspeaker cone 11 i.e. in this embodiment, the front of cone 11 of the loudspeaker is sealed within resonant cavity 17 while the back (rear) is oriented toward the outside; in this way, the thickness of resonant cavity 17 will no longer be constrained by the thickness of cone 11 as shown in Figure 3. This embodiment is suitable for many applications where the thickness is particularly constrained. It will suffice to allow the axis part of the loudspeaker to have a tolerance space for its cone 11 in the axial direction. For cone frame 10, the thickness of its resonant cavity 17 can be designed based on requirements. Further, a loudspeaker with a cone 11 with large stroke can be selected to obtain a better effect.

The description above only covers the preferred embodiments of this invention and it is not meant to limit its implementation scope i.e. any equivalent changes or modifications made within the patent scope of this invention or based on its specification content should all fall within the scope of this invention.

Claims

1. The coaxial diaphragm loudspeaker unit includes an electromagnetic loudspeaker. This electromagnetic loudspeaker includes a cone that is driven by a voice coil and a cone frame to secure the cone; a characteristic is its additional inclusion of a passive diaphragm; the said passive diaphragm is secured on the said cone frame using elastic components. It is coaxial with the said cone and has a ring-shaped circumference distributed outside it; at the same time, one side of the said passive diaphragm has a sealed connection to the air of one side of the said cone; the other side of the said passive diaphragm and the other side of the said cone are both exposed to the open space.

2. As per the coaxial diaphragm loudspeaker unit described in patent claim 1 , a characteristic is that both the said cone and the said passive diaphragm are rotationally symmetric.

3. As per the coaxial diaphragm loudspeaker unit described in patent claim 1 , a characteristic is that the said passive diaphragm has a flat form.

4. As per the coaxial diaphragm loudspeaker unit described in patent claim 1 , a characteristic is that the radius of the said passive diaphragm gradually decreases along its axial direction.

5. As per the coaxial diaphragm loudspeaker unit described in patent claim 1 , a characteristic is that one side of the said passive diaphragm has a sealed connection to the front air of the said cone.

6. As per the coaxial diaphragm loudspeaker unit described in patent claim 1 , a characteristic is that one side of the said passive diaphragm has a sealed connection to the rear air of the said cone.

7. The characteristics of the mirror coaxial diaphragm speaker include:

Two loudspeakers are situated axially opposite to mirror each other, and the pair is secured on a cone frame; also, the coaxial passive diaphragm has a ring-shaped circumference distributed coaxially at the periphery of the cone of the said loudspeaker. It is secured on the said cone frame using elastic components, and this setup is correspondingly mirrored for every said loudspeaker; further, the same side of the said coaxial passive diaphragm and the same side of the said cone are connected to one part of the said cone frame to jointly form a sealed resonant cavity; the other side of the said coaxial passive diaphragm and the other side of the said cone are jointly exposed to the open space.

8. As per the mirror coaxial diaphragm speaker described in patent claim 7, a characteristic is that the cone front of the said loudspeaker is located in the said resonant cavity.

9. As per the mirror coaxial diaphragm speaker described in patent claim 7, a characteristic is that the cone rear of the said loudspeaker is located in the said resonant cavity.

10. As per the mirror coaxial diaphragm speaker described in patent claim 7, a characteristic is that the said coaxial passive diaphragm has a flat form.

11. As per the mirror coaxial diaphragm speaker described in patent claim 7, a characteristic is that the radius of the said coaxial passive diaphragm gradually decreases along its axial direction.

12. As per the mirror coaxial diaphragm speaker described in patent claim 7, a characteristic is that the cone and passive diaphragm of the said loudspeaker are rotationally symmetric.