PATENT DOCUMENT

Publication Number: US-9712921-B2
Application Number: US-201414468178-A
Country: US
Kind Code: B2

Title: High aspect ratio microspeaker having a two-plane suspension

Abstract:
A microspeaker includes a frame and a diaphragm having length sides that are longer than its width sides. A magnet is positioned below the diaphragm. A yoke includes a base portion positioned below the magnet and sidewalls which extend from the base portion, the yoke sidewalls positioned only along a length dimension of the magnet. A voice coil includes an upper end attached to a bottom face of the diaphragm and a lower end positioned within a gap formed between the length dimension of the magnet and the yoke sidewalls. A first suspension member is attached to the length sides and the width sides of the diaphragm and the frame. The first suspension member is within a first plane. A second suspension member is attached to the lower end of the voice coil and the frame. The second suspension member is in a second plane different from the first plane.

Claims:
What is claimed is: 
     
       1. A microspeaker comprising:
 a frame; 
 a diaphragm positioned within the frame, the diaphragm having length sides and width sides, wherein the length sides are longer than the width sides; 
 a magnet positioned below the diaphragm; 
 a yoke having a base portion positioned below the magnet and yoke sidewalls which extend from the base portion, the yoke sidewalls positioned only along a length dimension of the magnet; 
 a voice coil having an upper end attached to a bottom face of the diaphragm and a lower end positioned within a gap formed between the length dimension of the magnet and the yoke sidewalls; 
 a first suspension member having an inner edge attached to the length sides and the width sides of the diaphragm and an outer edge extending to the frame, wherein the first suspension member is within a first plane; and 
 a second suspension member having an inner edge attached to the lower end of the voice coil and an outer edge attached to the frame, wherein the second suspension member is in a second plane different from the first plane and the second suspension member is less compliant in an x-direction than a z-direction. 
 
     
     
       2. The microspeaker of  claim 1  wherein the inner edge of the second suspension member is attached only to a portion of the lower end of the voice coil positioned along the width sides of the diaphragm. 
     
     
       3. The microspeaker of  claim 1  wherein the second suspension member has a rectangular profile. 
     
     
       4. The microspeaker of  claim 1  wherein the second suspension member is a solid membrane having a width equal to that of the voice coil. 
     
     
       5. The microspeaker of  claim 1  wherein the second suspension member comprises two separate suspension members extending from opposing ends of the voice coil. 
     
     
       6. The microspeaker of  claim 1  wherein the second suspension member is doped with a conductive material such that the second suspension member is operable to electrically connect the voice coil to circuitry within the frame. 
     
     
       7. The microspeaker of  claim 1  wherein the second suspension member is a layered membrane, the layered membrane including at least one electrically conductive layer. 
     
     
       8. The microspeaker of  claim 1  wherein the first plane is above the voice coil and the second plane is below the voice coil. 
     
     
       9. The microspeaker of  claim 1  wherein an opening is formed in at least one of the yoke sidewalls and the second suspension member extends through the opening to the frame. 
     
     
       10. A transducer comprising:
 a frame; 
 a sound radiating surface positioned within the frame, the sound radiating surface having length sides and width sides, wherein the length sides are longer than the width sides; 
 a voice coil having an upper end attached to a bottom face of the sound radiating surface and a lower end; 
 a magnet assembly having a magnet and a yoke, the magnet and the yoke dimensioned to form magnetic gaps below only the length sides of the sound radiating surface, wherein the lower end of the voice coil is positioned within the magnetic gaps; 
 an upper suspension member connecting the sound radiating surface to the frame, wherein the upper suspension member is above the voice coil; and 
 a lower suspension member connecting the voice coil to the frame, wherein the lower suspension member is attached to a portion of the lower end of the voice coil positioned outside of the magnetic gaps such that the lower suspension member is below the voice coil, and the lower suspension member is stiffer in an x-direction parallel to a surface of the lower suspension member than a z-direction normal to the surface of the lower suspension member. 
 
     
     
       11. The transducer of  claim 10  wherein the sound radiating surface has an aspect ratio greater than or equal to 2.0. 
     
     
       12. The transducer of  claim 10  wherein the lower suspension member comprises a first lower suspension member and a second lower suspension member, each of the first lower suspension member and the second lower suspension member being separable structures attached to different portions of the lower end of the voice coil. 
     
     
       13. The transducer of  claim 12  wherein the first lower suspension member radiates outwardly from a width side of the voice coil to the frame and the second lower suspension member radiates outwardly from another width side of the voice coil to the frame. 
     
     
       14. The transducer of  claim 10  wherein the magnet is a rectangular magnet and the yoke comprises sidewalls positioned along only a length dimension of the rectangular magnet such that the magnetic gaps are formed only along the length dimension of the magnet. 
     
     
       15. A microspeaker comprising:
 a frame; 
 a diaphragm positioned within the frame, the diaphragm having a high aspect ratio; 
 a magnet positioned below the diaphragm, 
 a yoke having a base portion positioned below the magnet and yoke sidewalls which extend from the base portion, the yoke sidewalls positioned along only two sides of the magnet; 
 a voice coil having length sides and width sides, each of the length sides and width sides having an upper end attached to a bottom face of the diaphragm and a lower end positioned within a gap formed between the magnet and the yoke sidewalls; 
 an upper suspension member connecting the diaphragm to the frame, wherein the upper suspension member is above the voice coil; and 
 a lower suspension member connecting the lower end of the voice coil to the frame such that the lower suspension member is below the voice coil, wherein the lower suspension member is attached to the lower end of only the width sides of the voice coil and wherein the lower suspension member is dimensioned to have a lower compliance in an x-direction than a z-direction. 
 
     
     
       16. The microspeaker of  claim 15  wherein the high aspect ratio comprises an aspect ratio greater than or equal to 2.0. 
     
     
       17. The microspeaker of  claim 15  wherein the lower suspension member comprises a first section and a second section that are separately attached to the width sides. 
     
     
       18. The microspeaker of  claim 15  wherein the voice coil has a rectangular profile.

Description:
FIELD 
     An embodiment of the invention is directed to a speaker having a dual suspension system, more specifically, a high aspect ratio microspeaker having a two-plane suspension system to improve diaphragm stability. Other embodiments are also described and claimed. 
     BACKGROUND 
     In modern consumer electronics, audio capability is playing an increasingly larger role as improvements in digital audio signal processing and audio content delivery continue to happen. In this aspect, there is a wide range of consumer electronics devices that can benefit from improved audio performance. For instance, smart phones include, for example, electro-acoustic transducers such as speakerphone loudspeakers and earpiece receivers that can benefit from improved audio performance. Smart phones, however, do not have sufficient space to house much larger high fidelity sound output devices. This is also true for some portable personal computers such as laptop, notebook, and tablet computers, and, to a lesser extent, desktop personal computers with built-in speakers. Many of these devices use what are commonly referred to as “microspeakers.” Microspeakers are a miniaturized version of a loudspeaker, which use a moving coil motor to drive sound output. The moving coil motor may include a diaphragm, voice coil and magnet assembly positioned within a frame. Due to height limitations, the diaphragm is typically suspended within the frame by a single plane suspension system. In some instances, the diaphragm may have a relatively high aspect ratio of length to width that can lead to an increased risk of stability problems such as an increase in the severity of the moving assembly&#39;s rocking mode. For example, as the aspect ratio of the diaphragm increases (i.e. the ratio of the long dimension, length, to the short dimension, width, increases), the risk of rocking or twisting along the length dimension of the diaphragm may increase. 
     SUMMARY 
     An embodiment of the invention is directed to a high aspect ratio microspeaker having a dual suspension system that helps to stabilize and/or suppress one or more rocking modes of a diaphragm suspended therein. Representatively, in one embodiment, the microspeaker includes a frame and a diaphragm positioned within the frame. The diaphragm may have a length and width. The length may be longer than the width. For example, a ratio of the length to the width may be 2.0 or greater such that the diaphragm is considered to have a high aspect ratio. A magnet may be positioned below the diaphragm. The microspeaker may further include a yoke that includes a base portion positioned below the magnet, and sidewalls which extend from the base portion. The yoke sidewalls may be positioned only along a length dimension (or long side) of the magnet such that magnetic gaps between the yoke sidewalls and the magnet are formed only along the length of the magnet. In this aspect, the ends of the yoke may be considered open. A voice coil having an upper end attached to a bottom face of the diaphragm and a lower end positioned within the gap formed between a long side of the magnet and the yoke sidewall may further be provided. The microspeaker may further include a primary, or first, suspension member and a secondary, or second, suspension member. The first suspension member may include an inner edge attached to the length sides and the width sides of the diaphragm and an outer edge attached to the frame. The first suspension member may be within a first plane. The second suspension member may have an inner edge attached to the lower end of the voice coil and an outer edge attached to the frame. The second suspension member may be within a second plane different from the first plane. For example, the first suspension member may be within an upper plane which is above the voice coil and the second suspension member may be in a lower plane which is below the voice coil. In one aspect, the second suspension member may be attached to, and extend from, only two of the four sides of a rectangular voice coil, in particular the width sides, to provide added stability to the diaphragm. 
     Another embodiment of the invention is directed to a transducer including a frame and a sound radiating surface positioned within the frame. The sound radiating surface may have length sides and width sides. The length sides may be longer than the width sides. A voice coil, having an upper end and a lower end, may be attached to a bottom face of the diaphragm at its upper end. The transducer may further include a magnet assembly. The magnet assembly may include a magnet and a yoke. The magnet and the yoke may be dimensioned to form magnetic gaps below only the length sides of the sound radiating surface. The lower end of the voice coil may be positioned within the magnetic gaps. The transducer may further include an upper suspension member and a lower suspension member. The upper suspension member may connect the sound radiating surface to the frame and be above the voice coil. The lower suspension member may connect the voice coil to the frame. In particular, the lower suspension member may be attached to a portion of the lower end of the voice coil positioned outside of the magnetic gaps such that it is below the voice coil. 
     Another embodiment of the invention is directed to a microspeaker having a frame and a diaphragm positioned in the frame. The diaphragm may have a high aspect ratio, for example, an aspect ratio greater than or equal to 2.0. A magnet and a yoke may be positioned below the diaphragm. The yoke may have a base portion positioned below the magnet and sidewalls which extend from the base portion along only two sides of the magnet. The microspeaker further includes a voice coil having length sides and width sides, each of the length sides and width sides having an upper end attached to a bottom face of the diaphragm and a lower end positioned within a gap formed between the magnet and the sidewalls of the yoke. An upper suspension member connects the diaphragm to the frame and is above the voice coil. A lower suspension member connects the lower end of the voice coil to the frame and is below the voice coil. The lower suspension member may be attached to the lower end of only the width sides of the voice coil to help stabilize rocking of the diaphragm. 
     The above summary does not include an exhaustive list of all aspects of the present invention. It is contemplated that the invention includes all systems and methods that can be practiced from all suitable combinations of the various aspects summarized above, as well as those disclosed in the Detailed Description below and particularly pointed out in the claims filed with the application. Such combinations have particular advantages not specifically recited in the above summary. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and they mean at least one. 
         FIG. 1A  illustrates a cross-sectional side view of one embodiment of a transducer. 
         FIG. 1B  illustrates a cross-sectional side view of the transducer of  FIG. 1A  along line B-B′. 
         FIG. 2  illustrates a top plan view of a diaphragm and a primary suspension member of the transducer of  FIG. 1A . 
         FIG. 3  illustrates a bottom plan view of a diaphragm and a secondary suspension member of the transducer of  FIG. 1A . 
         FIG. 4  illustrates a top plan view of a magnet assembly of the transducer of  FIG. 1A . 
         FIG. 5  illustrates a bottom plan view of another embodiment of a diaphragm and a secondary suspension member of a transducer. 
         FIG. 6  illustrates a top plan view of another embodiment of a magnet assembly used with the transducer of  FIG. 5 . 
         FIG. 7  illustrates a cross-sectional side view of one embodiment of a conductive suspension member. 
         FIG. 8  illustrates a cross-sectional side view of another embodiment of a conductive suspension member. 
         FIG. 9  illustrates a cross-sectional side view of an embodiment of a transducer including a conductive suspension member. 
         FIG. 10  illustrates a cross-sectional side view of another embodiment of a transducer including a conductive suspension member. 
         FIG. 11  illustrates one embodiment of a simplified schematic view of one embodiment of an electronic device in which a transducer may be implemented. 
         FIG. 12  illustrates a block diagram of some of the constituent components of an embodiment of an electronic device in which an embodiment of the invention may be implemented. 
     
    
    
     DETAILED DESCRIPTION 
     In this section we shall explain several preferred embodiments of this invention with reference to the appended drawings. Whenever the shapes, relative positions and other aspects of the parts described in the embodiments are not clearly defined, the scope of the invention is not limited only to the parts shown, which are meant merely for the purpose of illustration. Also, while numerous details are set forth, it is understood that some embodiments of the invention may be practiced without these details. In other instances, well-known structures and techniques have not been shown in detail so as not to obscure the understanding of this description. 
       FIG. 1A  illustrates a cross-sectional side view of one embodiment of a transducer. Transducer  100  may be, for example, an electro-acoustic transducer that converts electrical signals into audible signals that can be output from a device within which transducer  100  is integrated. For example, transducer  100  may be a microspeaker such as a speakerphone speaker or an earpiece receiver found within a smart phone, or other similar compact electronic device such as a laptop, notebook, or tablet computer. Transducer  100  may be enclosed within a housing or enclosure of the device within which it is integrated. In some embodiments, transducer  100  may be considered a high aspect ratio microspeaker. The phrase “high aspect ratio” refers to a high ratio between a length dimension and a width dimension of a particular structure, in this case a microspeaker. For example, a ratio between a length dimension and a width dimension of 2.0 or greater is considered to be a “high aspect ratio.” 
     Transducer  100  may include a sound radiating surface (SRS) or diaphragm  102 . Diaphragm  102  may include a sound radiating surface and be any type of diaphragm or sound radiating surface capable of vibrating in response to an acoustic signal to produce acoustic or sound waves. In one embodiment, diaphragm  102  may have a high aspect ratio. For example, diaphragm  102  may have a length dimension and width dimension and a ratio of the length dimension (or length sides) to the width dimension (or width sides) is high, for example, 2.0 or greater. In this aspect, diaphragm  102  may have, for example, a substantially rectangular or otherwise elongated shape.  FIG. 1A  illustrates a cross-section through the length dimension or long side of diaphragm  102 . 
     Transducer  100  may also include a voice coil  114  positioned along a bottom face  122  of diaphragm  102  (i.e. a face of diaphragm  102  facing magnet assembly  132 ). For example, in one embodiment, voice coil  114  includes an upper end  124  and a lower end  126 . The upper end  124  may be directly attached to the bottom face  122  of diaphragm  102 , such as by chemical bonding or the like. In another embodiment, voice coil  114  may be wrapped around a former or bobbin and the former or bobbin is directly attached to the bottom face  122  of diaphragm  102 . In one embodiment, voice coil  114  may have a similar profile and shape to that of diaphragm  102 . For example, where diaphragm  102  has length sides greater than the width sides (e.g. a rectangular shape), voice coil  114  may also have length sides (i.e. a length dimension) that are greater than its width sides (i.e. a width dimension). For example, voice coil  114  may have a substantially rectangular or racetrack shape. The ratio of the length sides to the width sides may be such that voice coil  114  is considered to have a high aspect ratio, for example, an aspect ratio greater than or equal to 2.0. 
     Diaphragm  102 , with voice coil  114  attached thereto, may be suspended within frame  104  by a primary suspension member  106  and a secondary suspension member  116 . In one embodiment, each of primary suspension member  106  and secondary suspension member  116  may have what is considered a “rolled” configuration in that they have a bowed or curved region which allows for greater compliance in the z-direction  152 , and in turn, facilitates an up and down movement, also referred to as a vibration, of the diaphragm  102 . Primary suspension member  106  and secondary suspension member  116  may be within different planes. For example, primary suspension member  106  may be in one plane  128  and secondary suspension member  116  may be in another plane  130 . Plane  128  may be considered an upper plane while plane  130  may be considered a lower plane such that primary suspension member  106  is an upper suspension member (i.e. above secondary suspension member  116 ) and secondary suspension member  116  is a lower suspension member (i.e. below primary suspension member  106 ). Said another way, primary suspension member  106  may be above voice coil  114  and secondary suspension member  116  may be below voice coil  114 . 
     Primary suspension member  106  may be the primary means by which diaphragm  102  is suspended within frame  104  and which allows for diaphragm  102  to act as a sound radiating surface. In this aspect, primary suspension member  106  may include an inner edge  108  and an outer edge  110 . The inner edge  108  may be attached (e.g. adhered or chemically bonded) along a perimeter edge  112  of diaphragm  102  and the outer edge  110  may be attached (e.g. adhered or chemically bonded) to frame  104 . Primary suspension member  106  may be attached around all sides of diaphragm  102  such that diaphragm  102  is essentially sealed around all sides to frame  104 . In this aspect, where diaphragm  102  has a high aspect ratio, or rectangular shape, primary suspension member  106  may have a similar profile. 
     Secondary suspension member  116  may provide a secondary means by which diaphragm  102 , and voice coil  114 , are suspended within frame  104 . In this aspect, the primary purpose of secondary suspension member  116  may be to provide stability to diaphragm  102 . For example, secondary suspension member  116  may be configured to suppress a rocking mode of the diaphragm. The term “rocking” or “rocking mode” refers to an undesirable rocking that can happen to speaker diaphragms (or other speaker components) at certain frequencies. Representatively, at certain frequencies, the diaphragm may begin to rock or otherwise move out of phase in an undesirable non-axial direction with respect to other components (e.g. the suspension member) and therefore a decrease in sound pressure output from the transducer may occur. By stabilizing the diaphragm (i.e. suppressing the rocking mode), the frequency at which diaphragm rocking occurs may be increased to a frequency which is, for example, above the working range of the transducer. The higher the frequency of the rocking mode is made, the less severe its effect tends to be, making it less detrimental to the performance of the device. 
     In the case of a high aspect ratio diaphragm such as diaphragm  102 , one rocking mode may occur along a longitudinal axis (i.e. axis running along the length dimension) and another rocking mode may occur along a lateral axis (i.e. axis running along the width dimension) of diaphragm  102 . Said another way, diaphragm  102  may be subject to a first rocking mode which can be described as twisting along the length dimension (i.e. rocking or tilting from side to side along the longitudinal axis) and a second rocking mode which can be described as rocking or tilting forward and backward along the lateral axis. Secondary suspension member  116  is therefore designed to suppress one or more of these rocking modes. 
     Representatively, in one embodiment, secondary suspension member  116  may include a first section  116 A and a second section  116 B. Each of the first section  116 A and second section  116 B may be entirely separate structures that are separately attached to voice coil  114 . In other words, first section  116 A and second section  116 B are not directly connected to one another. The first section  116 A may be attached to one of the width sides of voice coil  114  and the second section  116 B may be attached to another of the width sides of voice coil  114 . In one embodiment, each of first section  116 A and second section  116 B may be attached to only the width sides of voice coil  114 . In other words, suspension member  116  is not present along (e.g. is not directly in contact with) the length sides of voice coil  114 . In this aspect, first section  116 A and second section  116 B may be considered to radiate outwardly from each of the width sides of voice coil  114 . Representatively, first section  116 A may include an inner edge  118 A and an outer edge  120 A. The inner edge  118 A may be attached (e.g. by an adhesive or chemical bonding), to the lower end of one of the width side of voice coil  114  and the outer edge  120 A may be attached (e.g. by an adhesive or chemical bonding) to frame  104 . Similarly, second section  116 B may include an inner edge  118 B and an outer edge  120 B. The inner edge  118 B may be attached (e.g. by an adhesive or chemical bonding), to the lower end of the other width side of voice coil  114  and the outer edge  120 B may be attached to the frame  104 . Since the voice coil  114  is attached to diaphragm  102 , both the voice coil  114  and diaphragm  102  are supported and/or suspended within frame  104  by secondary suspension member  116 . Alternatively, where voice coil  114  is wrapped around a former or bobbin, first and second sections  116 A,  116 B of secondary suspension member  116  may be optionally attached to a lower end of the former or bobbin. 
     First section  116 A and second section  116 B may be of a size and shape operable to suppress one or more of the previously discussed rocking modes of diaphragm  102 . Representatively, in one embodiment, first section  116 A and second section  116 B may be configured to be stiffer in an x-direction  154  than in a z-direction  152 . Said another way, first section  116 A and second section  116 B may be more compliant in a z-direction  152  than in an x-direction  154 . In this aspect, due to the stiffness of first and second sections  116 A,  116 B and their location along the width sides of voice coil  114  (and, in turn, diaphragm  102 ) the rocking modes of diaphragm  102  along the longitudinal axis and lateral axis of diaphragm  102  are suppressed without suppressing a vibrational (or up and down) movement of diaphragm  102  in the z-direction  152 . The specific shape and dimensions of first section  116 A and  116 B will be discussed in more detail in reference to, for example,  FIG. 3  and  FIG. 5 . 
     Transducer  100  may further include a magnet assembly  132 . Magnet assembly  132  may include a magnet  134  (e.g. a NdFeB magnet), with a top plate  136  and a yoke  138  for guiding a magnetic circuit generated by magnet  134 . Magnet assembly  132 , including magnet  134 , top plate  136  and yoke  138 , may be positioned below diaphragm  102 , in other words, magnet assembly  132  is positioned between diaphragm  102  and frame  104 . In one embodiment, magnet  134  may be a center magnet positioned entirely within an open center of voice coil  114 . In this aspect, magnet  134  may have a similar profile as voice coil  114 , for example, length sides which are greater than its width sides, for example, a rectangular or elliptical shape. 
     Yoke  138  may be dimensioned to allow secondary suspension member sections  116 A and  116 B to extend from the width sides of voice coil  114  to frame  104 . Representatively, yoke  138  may include cutout sections near the width sides of voice coil  114 . For example, as can be seen from  FIG. 1A , which is a cross-section along the length dimension of yoke  138  and  FIG. 1B  which is a cross-section along line B-B′ of  FIG. 1A , in other words a width dimension of yoke  138 , yoke  138  includes a base portion  140  below magnet  134  and sidewalls  142 ,  144 . Sidewalls  142 ,  144  extend from base portion  140  only along the length sides of magnet  134  and voice coil  114 . In other words, when transducer  100  is viewed from the length side (i.e.  FIG. 1A ), yoke  138  looks like a substantially planar structure but when viewed from the width side (i.e.  FIG. 1B ), yoke  138  appears as a channel or substantially “U” shaped type structure. In this aspect, magnetic gaps  146 A and  146 B between magnet  134  and yoke  138  are formed only along the length sides or length dimension of voice coil  114 , and in turn only below the length sides of diaphragm  102 . In this aspect, only the lower end of the length sides of voice coil  114  are positioned within magnetic gaps  146 A and  146 B. In this aspect, the magnetic field produced within magnetic gaps  146 A and  146 B can be used to drive movement of voice coil  114 . In other embodiments, to accommodate the secondary suspension member sections  116 A and  116 B extending from the width sides of voice coil  114  to frame  104 , sections  116 A and  116 B may include cutout central regions and yoke  138  may include narrow sidewalls along the width sides of the magnet  134  and voice coil  114 , and fit within the center cutout regions such that sections  116 A and  116 B can extend to the frame. In this aspect, the yoke sidewalls are considered to be primarily along the length dimension of magnet  134  and voice coil  114 . 
     It is noted that since magnetic gaps  146 A and  146 B are formed along the long sides of voice coil  114  and diaphragm  102 , a sufficient force is generated to drive movement of voice coil  114 , and in turn, a vibration of diaphragm  102 , in the absence of a strong magnetic force along the width sides of voice coil  114  where no yoke side walls are present. In particular, in the case of microspeakers having a length side (or dimension) longer than the width side (or dimension), the force generated by the voice coil to vibrate the diaphragm is the sum of the force generated by the long side or dimension of the voice coil and the force generated by the short side or dimension of the voice coil. As the aspect ratio increases, however, the short side contributes less of the total force generated as compared to the long side. In fact, in the case of a high aspect ratio voice coil, the force generated by the short sides of the voice coil become virtually negligible. In this aspect, when the short sides of the voice coil generate negligible force, any effect on acoustic performance due to eliminating the magnetic gap along the short side by removing the yoke within this region is negligible. 
     The specific aspects of the primary suspension member  106  and secondary suspension member  116  will now be described in more detail in reference to  FIG. 2  and  FIG. 3 . Representatively,  FIG. 2  illustrates a top plan view of the diaphragm and the primary suspension member of the transducer of  FIG. 1A .  FIG. 3  illustrates a bottom plan view of the diaphragm and secondary suspension member of the transducer of  FIG. 1A . 
     Returning to  FIG. 2 , from this view, it can be seen that diaphragm  102  has a length dimension (l- 1 ) and a width dimension (w- 1 ). The length dimension (l- 1 ) is longer than the width dimension (w- 1 ). In some embodiments, the ratio of the length dimension (l- 1 ) to width dimension (w- 1 ) is high such that diaphragm  102  is considered to have a high aspect ratio. For example, the ratio of l- 1  to w- 1  is greater than or equal to 2.0. Said another way, diaphragm  102  includes length sides  202 A and  202 B and width sides  204 A and  204 B. The length sides  202 A,  202 B are longer than the width sides  204 A,  204 B. In the case of a high aspect ratio diaphragm  102 , the ratio of the length sides  202 A,  202 B to width sides  204 A,  204 B is greater than or equal to 2.0. Primary suspension member  106  extends entirely around diaphragm  102 . In some cases, primary suspension member  106  has as similar profile to that of diaphragm  102 , for example, a rectangular profile. Primary suspension member  106  may be sealed to each of the length sides  202 A,  202 B and width sides  204 A,  204 B of diaphragm  102  such that diaphragm  102  can be attached on all sides to the frame  104 . 
     In contrast, as can be seen from  FIG. 3 , which shows diaphragm  102 , voice coil  114  and secondary suspension member  116  from the bottom sides, secondary suspension member  116  is attached to only the width sides of voice coil  114  and is therefore below only the width sides  204 A,  204 B of diaphragm  102 . In particular, voice coil  114  may have a similar profile and shape as diaphragm  102 . In other words, voice coil  114  may have a length dimension (l- 2 ) and a width dimension (w- 2 ). The length dimension (l- 2 ) may be longer than the width dimension (w- 2 ). In some embodiments, the ratio of the length dimension (l- 2 ) to width dimension (w- 2 ) is high such that voice coil  114  is considered to have a high aspect ratio. For example, the ratio of l- 2  to w- 2  is greater than or equal to 2.0. Said another way, voice coil  114  includes length sides  302 A and  302 B and width sides  304 A and  304 B. The length sides  302 A,  302 B are longer than the width sides  304 A,  304 B. In the case of a high aspect ratio voice coil  114 , the ratio of the length sides  302 A,  302 B to width sides  304 A,  304 B is greater than or equal to 2.0. 
     In order to provide stability to diaphragm  102  against rocking modes, as previously discussed, the first section  116 A and second section  116 B of secondary suspension member  116  are attached to only the width sides  304 A,  304 B of voice coil  114 , respectively. By attaching sections  116 A,  116 B of suspension member  116  to only the width sides  304 A,  304 B of voice coil  114 , which is attached to diaphragm  102 , a stability of diaphragm  102  can be improved. More specifically, sections  116 A,  116 B are stiffer (i.e. less compliant) in the x-direction  154  that in the z-direction  152 . Because sections  116 A,  116 B are in turn attached to the width sides  304 A,  304 B of voice coil  114 , which are attached to the width sides  204 A,  204 B of diaphragm  102 , rocking or twisting of diaphragm  102  along its longitudinal axis (axis perpendicular to the x-direction  154 ) can be suppressed and/or reduced. In addition, a second rocking mode (i.e. front to back movement of the diaphragm  102  along the lateral axis, which is parallel to x-direction  154 ) can also be suppressed by sections  116 A,  116 B. 
     In one embodiment, sections  116 A,  116 B have a greater stiffness in the x-direction  154  due to their size and shape. Representatively, sections  116 A,  116 B may have a width dimension (w- 3 ) which is equal to that of voice coil  114 . For example, sections  116 A,  116 B may have the profile of a parallelogram (e.g. a rectangle) in which the width dimension (w- 3 ) is the same as that of the voice coil  114 . In addition, sections  116 A,  116 B may be solid membranes which have no openings therefore further increasing the stiffness in the x-direction  154 . Sections  116 A,  116 B may also be made of a relatively thin material such as thin polyimide film such as Kapton® and/or a meta-aramid material such as Nomex® which allows for a higher stiffness in the x-direction  154  while still maintaining compliance (or lower stiffness) in the z-direction so as not to interfere with the up and down movement (i.e. vibration) of diaphragm  102 . 
     It is noted that as can be seen from  FIG. 3 , only the width sides  304 A,  304 B, and not the length sides  302 A,  302 B, of voice coil  114  are in contact with sections  116 A,  116 B of secondary suspension member  116 . The length sides  302 A,  304 B of voice coil  114 , and in turn diaphragm  102 , are therefore free of any sort of secondary suspension member. Such a configuration further allows for the desired rocking mode suppression while still maintaining the desired compliance in the z-direction  152  so as not to interfere with a vibration of diaphragm  102 . 
       FIG. 4  illustrates a top plan view of a magnet assembly of the transducer of  FIG. 1A . This view further illustrates that magnet  134  may have a length dimension (l- 4 ) which is longer than the width dimension (w- 4 ). In other words, magnet  134  may have length sides  402 A,  402 B and width sides  404 A,  404 B. In some cases, an aspect ratio of length sides  402 A,  402 B to width sides  404 A,  404 B is high, for example, greater than or equal to 2.0 such that magnet  134  is considered to have a high aspect ratio. As can be further seen from this view, the sidewalls  142 ,  144  of yoke  138  are only along the length sides  402 A,  402 B of magnet  134  such that magnetic gaps  146 A,  146 B are formed only along the length sides  402 A,  402 B of magnet  134 . These magnetic gaps  146 A,  146 B are in turn, only below the length sides of voice coil  114  and diaphragm  102  as previously discussed. The ends of yoke  138  are therefore considered cut off, or open, such that there is room for secondary suspension member sections  116 A,  116 B to extend from the width sides of voice coil  114  and out yoke  138  to the frame  104 . 
       FIG. 5  illustrates a bottom plan view of another embodiment of a diaphragm and a secondary suspension member of a transducer. In this embodiment, the secondary suspension member includes four sections, namely the previously discussed first and second sections  116 A,  116 B, which extend from the width sides of voice coil  114 , as well as third and fourth sections  116 C and  116 D which extend from length sides of voice coil  114  for added stability. The third and fourth sections  116 C,  116 D may be substantially similar to sections  116 A,  116 B in size and shape, the only difference being they are attached to and radiate outwardly from the length dimension of voice coil  114 . 
       FIG. 6  illustrates a top plan view of another embodiment of a magnet assembly used with the transducer configuration of  FIG. 5 . Representatively, in order to accommodate the third and fourth suspension member sections  116 C,  116 D as previously discussed, yoke  138  includes additional cut out sections  602  and  604  within the sidewalls  142 ,  144 , respectively. The cut out sections  602 ,  604  are of a size and shape sufficient to allow sections  116 C,  116 D to extend through them and connect to the frame  104 , while still allowing magnetic gaps  146 A,  146 B to generate a sufficient magnetic force to drive movement of diaphragm  102 . In other words, cut out sections  602 ,  604 , and in turn, suspension sections  116 C and  116 D, should be relatively narrow so that a substantial portion of the sidewalls  142 ,  144 , which form the magnetic gaps to drive voice coil  114 , are maintained. 
       FIG. 7  illustrates a cross-sectional side view of one embodiment of an electrically conductive suspension member. Suspension member  700  may be any one or more of the previously discussed suspension members, namely primary suspension member  106  or secondary suspension member  116 , which are used to suspend a diaphragm and/or voice coil within a transducer as will be discussed in more detail in reference to  FIG. 9  and  FIG. 10 . Suspension member  700  may be, in this embodiment, an electrically conductive suspension membrane which can be used to electrically connect the voice coil of the transducer to the frame. Representatively, suspension member  700  may include a film or membrane  702  which is doped with a conductive dopant  704 . The film or membrane  702  may be, for example, made of a thermoformable plastic material, for example, a polyurethane (PU), a thermoplastic polyurethane (TPU), polyether ether ketone (PEEK) or the like. The conductive dopant  704  may be any conductive material suitable for doping a thermoformable plastic. For example, the conductive material may be a carbon nanotube. The film or membrane  702  may be formed and then doped with a conductive dopant  704 , or may be doped before membrane formation according to any standard doping technique. 
       FIG. 8  illustrates a cross-sectional side view of another embodiment of a conductive suspension member. Suspension member  800  may also be an electrically conductive membrane or film which can be used as a primary suspension member or a secondary suspension member to electrically connect the voice coil to the frame, except in this embodiment, suspension member  800  is made of a multilayered membrane  802 . Representatively, the multilayered membrane  802  may include a bottom layer  804 , a middle layer  806  and a top layer  808 . One of layers  804 ,  806  and  808  may be made of a conductive material. For example, in one embodiment, where the bottom layer  804  is to be in contact with the voice coil and provide an electrical connection to the frame, the bottom layer  804  may be made of a conductive material, the middle layer  806  may be made of an adhesive material and the top layer  808  may be made of a non-conductive material. In other embodiments, where the top layer  808  is to be in contact with the voice coil and provide an electrical connection to the frame, the top layer  808  may be made of a conductive material, the middle layer  806  may be made of an adhesive and the bottom layer  804  may be made of a non-conductive material. In both cases, the middle adhesive layer  806  may be used to adhere or bond the top layer  808  to the bottom layer  804 . It is further to be understood that although three layers are shown, more or fewer layers may be used as desired. For example, top layer  808  may be attached to bottom layer  804  by a chemical bonding technique and the middle adhesive layer  806  omitted. In this way, one layer may be optimized for best electrical conductivity while another layer may be optimized for best mechanical properties. 
       FIG. 9  illustrates a cross-sectional side view of a transducer including a conductive suspension member. Transducer  900  is substantially similar to transducer  100  previously discussed in reference to  FIG. 1A . Representatively, transducer  900  includes a diaphragm  902  and voice coil  914  which are suspended from frame  904  by a primary suspension member  906  and a secondary suspension member  916 . The secondary suspension member  916  may include a first section  916 A and a second section  916 B attached to the bottom end of voice coil  914  as previously discussed. A magnet assembly  932 , such as previously discussed magnet assembly  132 , is positioned below the diaphragm  902 . In this embodiment, the first section  916 A and second section  916 B of secondary suspension member  916  are shown as being conductive suspension members such as those described in reference to  FIG. 7  and  FIG. 8 . The conductive suspension member sections  916 A,  916 B are attached directly to the negative (−) and positive (+) terminals along the bottom end of voice coil  914 , respectively, at one end, and to circuitry  940  running through frame  904 , at another end. For example, in one embodiment, voice coil  914  may be a double wound coil having an inner layer  914 A electrically connected to the positive (+) terminal and an outer layer  914 B electrically connected to the negative (−) terminal. In this aspect, sections  916 A,  916 B can be used to electrically connect voice coil  914  to circuitry  940  within frame  904  without the need for lead wires which may be susceptible to breakage or fatigue during the normal operation of the transducer. This concept may be extended to any number of layers used in the coil construction, for example an even number of layers (e.g. 2, 4, 6, etc.) could be used when the connections are to be made to the same end of the coil, or an odd number of layers (e.g., 1, 3, 5, etc.) could be used if it were desired to make the (+) and (−) connection on opposite ends of the coil. 
       FIG. 10  illustrates a cross-sectional side view of another embodiment of a transducer including a conductive suspension member. Transducer  1000  is substantially similar to transducer  100  previously discussed in reference to  FIG. 1A . Representatively, transducer  1000  includes a diaphragm  1002  and voice coil  1014  which are suspended from frame  1004  by a primary suspension member  1006  and a secondary suspension member  1016 . The secondary suspension member  1016  may include a first section  1016 A and a second section  1016 B attached to the bottom end of voice coil  1014  as previously discussed. A magnet assembly  1032 , such as previously discussed magnet assembly  132 , is positioned below the diaphragm  1002 . In this embodiment, the primary suspension member  1006  is shown as being a conductive suspension member such as those described in reference to  FIG. 7  and  FIG. 8 . The conductive primary suspension member  1006  is attached directly to the negative (−) and positive (+) terminals at a top end of voice coil  1014  and to circuitry  1040  running through frame  1004 . For example, in one embodiment, voice coil  1014  may be a double wound coil having an inner layer  1014 A electrically connected to the positive (+) terminal and an outer layer  1014 B electrically connected to the negative (−) terminal. In this aspect, primary suspension member  1006  can be used to electrically connect voice coil  1014  to circuitry  1040  within frame  1004  without the need for lead wires which may be susceptible to breakage. It is noted that in cases where primary suspension member  1006  is one continuous membrane, such as primary suspension member  106  discussed in reference to  FIG. 2 , a conductive break may be formed within the membrane so as not to short circuit an electrical current through voice coil  1014 . The conductive break may be, for example, an area of non-conductivity between, for example, a left and right side, or a top and bottom, of the membrane. 
       FIG. 11  illustrates one embodiment of a simplified schematic view of one embodiment of an electronic device in which a transducer, such as that described herein, may be implemented. As seen in  FIG. 11 , the transducer may be integrated within a consumer electronic device  1102  such as a smart phone with which a user can conduct a call with a far-end user of a communications device  1104  over a wireless communications network; in another example, the transducer may be integrated within the housing of a tablet computer. These are just two examples of where the transducer described herein may be used, it is contemplated, however, that the transducer may be used with any type of electronic device in which a transducer, for example, a loudspeaker or receiver, is desired, for example, a tablet computer, a desk top computing device or other display device. 
       FIG. 12  illustrates a block diagram of some of the constituent components of an embodiment of an electronic device in which an embodiment of the invention may be implemented. Device  1200  may be any one of several different types of consumer electronic devices. For example, the device  1200  may be any transducer-equipped mobile device, such as a cellular phone, a smart phone, a media player, or a tablet-like portable computer. 
     In this aspect, electronic device  1200  includes a processor  1212  that interacts with camera circuitry  1206 , motion sensor  1204 , storage  1208 , memory  1214 , display  1222 , and user input interface  1224 . Main processor  1212  may also interact with communications circuitry  1202 , primary power source  1210 , speaker  1218 , and microphone  1220 . Speaker  1218  may be a microspeaker such as that described in reference to  FIG. 1A . The various components of the electronic device  1200  may be digitally interconnected and used or managed by a software stack being executed by the processor  1212 . Many of the components shown or described here may be implemented as one or more dedicated hardware units and/or a programmed processor (software being executed by a processor, e.g., the processor  1212 ). 
     The processor  1212  controls the overall operation of the device  1200  by performing some or all of the operations of one or more applications or operating system programs implemented on the device  1200 , by executing instructions for it (software code and data) that may be found in the storage  1208 . The processor  1212  may, for example, drive the display  1222  and receive user inputs through the user input interface  1224  (which may be integrated with the display  1222  as part of a single, touch sensitive display panel). In addition, processor  1212  may send an audio signal to speaker  1218  to facilitate operation of speaker  1218 . 
     Storage  1208  provides a relatively large amount of “permanent” data storage, using nonvolatile solid state memory (e.g., flash storage) and/or a kinetic nonvolatile storage device (e.g., rotating magnetic disk drive). Storage  1208  may include both local storage and storage space on a remote server. Storage  1208  may store data as well as software components that control and manage, at a higher level, the different functions of the device  1200 . 
     In addition to storage  1208 , there may be memory  1214 , also referred to as main memory or program memory, which provides relatively fast access to stored code and data that is being executed by the processor  1212 . Memory  1214  may include solid state random access memory (RAM), e.g., static RAM or dynamic RAM. There may be one or more processors, e.g., processor  1212 , that run or execute various software programs, modules, or sets of instructions (e.g., applications) that, while stored permanently in the storage  1208 , have been transferred to the memory  1214  for execution, to perform the various functions described above. 
     The device  1200  may include communications circuitry  1202 . Communications circuitry  1202  may include components used for wired or wireless communications, such as two-way conversations and data transfers. For example, communications circuitry  1202  may include RF communications circuitry that is coupled to an antenna, so that the user of the device  1200  can place or receive a call through a wireless communications network. The RF communications circuitry may include a RF transceiver and a cellular baseband processor to enable the call through a cellular network. For example, communications circuitry  1202  may include Wi-Fi communications circuitry so that the user of the device  1200  may place or initiate a call using voice over Internet Protocol (VOIP) connection, transfer data through a wireless local area network. 
     The device may include a microphone  1220 . Microphone  1220  may be an acoustic-to-electric transducer or sensor that converts sound in air into an electrical signal. The microphone circuitry may be electrically connected to processor  1212  and power source  1210  to facilitate the microphone operation (e.g. tilting). 
     The device  1200  may include a motion sensor  1204 , also referred to as an inertial sensor, that may be used to detect movement of the device  1200 . The motion sensor  1204  may include a position, orientation, or movement (POM) sensor, such as an accelerometer, a gyroscope, a light sensor, an infrared (IR) sensor, a proximity sensor, a capacitive proximity sensor, an acoustic sensor, a sonic or sonar sensor, a radar sensor, an image sensor, a video sensor, a global positioning (GPS) detector, an RF or acoustic doppler detector, a compass, a magnetometer, or other like sensor. For example, the motion sensor  1204  may be a light sensor that detects movement or absence of movement of the device  1200 , by detecting the intensity of ambient light or a sudden change in the intensity of ambient light. The motion sensor  1204  generates a signal based on at least one of a position, orientation, and movement of the device  1200 . The signal may include the character of the motion, such as acceleration, velocity, direction, directional change, duration, amplitude, frequency, or any other characterization of movement. The processor  1212  receives the sensor signal and controls one or more operations of the device  1200  based in part on the sensor signal. 
     The device  1200  also includes camera circuitry  1206  that implements the digital camera functionality of the device  1200 . One or more solid state image sensors are built into the device  1200 , and each may be located at a focal plane of an optical system that includes a respective lens. An optical image of a scene within the camera&#39;s field of view is formed on the image sensor, and the sensor responds by capturing the scene in the form of a digital image or picture consisting of pixels that may then be stored in storage  1208 . The camera circuitry  1206  may also be used to capture video images of a scene. 
     Device  1200  also includes primary power source  1210 , such as a built in battery, as a primary power supply. 
     While certain embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that the invention is not limited to the specific constructions and arrangements shown and described, since various other modifications may occur to those of ordinary skill in the art. For example, the dual suspension system transducers described herein could be acoustic-to-electric transducers or sensors that convert sound in air into an electrical signal, such as for example, a microphone. The description is thus to be regarded as illustrative instead of limiting.

Metadata:
Filing Date: 20140825
Publication Date: 20170718
Grant Date: 20170718
Priority Date: 20140825
Inventors: SALVATTI ALEXANDER V.
VIEITES PABLO SEOANE
CROSBY JUSTIN D.
PORTER SCOTT P.
SWEET EDWARD T.
BOOTHE DANIEL K.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R2307/204", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2307/207", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/025", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/046", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/043", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/04", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/025", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/046", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/043", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R9/046", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/025", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2307/204", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/04", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2307/204", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R9/043", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R9/043", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R2307/207", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2307/207", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R2499/11", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 53835536