JPH024197B2 - - Google Patents

Description

Claim 1: A diaphragm for use in an electroacoustic transducer having a plurality of spaced apart magnetic means, the diaphragm having a front surface and a rear surface, the series comprising a plurality of spaced magnetic means projecting from the rear surface. a folded sheet of film material having spaced apart, parallel, elongated, channel-shaped protrusions along its entire length; a thin, substantially flat sheet overlying and secured to a front surface of the folded sheet; sheets, electrically connected in parallel to each other, attached directly opposite each other to both sides of each of the groove-shaped protrusions of the folded sheet, and configured to electromagnetically cooperate with the magnetic means. a pair of first and second conductor means extending in alignment with the magnet means, each protrusion having a pair of side portions and a central portion interconnecting the pair of side portions; It has a part,
The first conductor means and the second conductor means extend in the form of a "Greek pattern" as conductor patterns that are mirror images of each other on both sides of the central part and the pair of side parts of each protrusion, a plurality of pairs of inwardly protruding gaskets spaced apart in the longitudinal direction of each of the protrusions are formed on side portions of each of the protrusions;
A diaphragm characterized in that each pair of gaskets are in contact with each other.

2. The diaphragm according to claim 1, wherein each of the protrusions is substantially U-shaped having a pair of side portions and a central portion interconnecting the pair of side portions.

3. The front surface of the folded sheet is formed by a series of substantially flat sections interconnecting each of the projections and lying substantially in a common plane. diaphragm.

4. The diaphragm according to claim 1, comprising a pair of end walls fixed to both ends of the folded sheet.

5 a first plate connected to both side edges of the folded sheet;
a pair of flexible connecting strips and a second pair of connecting strips connected to and extending from the end wall, the connecting strips comprising:
5. A diaphragm as claimed in claim 4, including mounting blocks for fixing them in position.

6. The diaphragm of claim 1, wherein each of said gussets extends into a web portion of said folded sheet that connects said projections to one another.

7. The diaphragm of claim 1, wherein said flat sheet is formed by a sheet of foam material having a plurality of depending ridges extending partially into said corresponding projections.

8. The diaphragm of claim 1, wherein said flat sheet has a series of spaced depending channels extending partially into said corresponding projections.

9. An electroacoustic transducer diaphragm for cooperating with a plurality of spaced apart magnetic means, the electroacoustic transducer diaphragm having substantially planar front and rear surfaces and having a plurality of mutually spaced diaphragms projecting from the rear surface. spaced elongated,
a folded sheet of film material molded or otherwise formed having groove-shaped protrusions along its entire length; and a substantially flat sheet overlying and affixed to the front surface of the folding sheet. thin sheets electrically connected to each other in parallel, attached directly opposite each other to both sides of each of the groove-shaped protrusions of the folded sheet, and cooperating electromagnetically with the magnetic means; a pair of first and second conductor means extending in alignment with the magnet means;

10 A diaphragm blank for forming a diaphragm of an electroacoustic transducer, wherein a pair of first
and a diaphragm blank comprising a sheet of heat-resistant thermoplastic film material having second conductor means.

11 The heat-resistant thermoplastic film material is 300
The diaphragm blank according to claim 10, which has an annealing temperature higher than (148.8° C.).

12. The diaphragm blank according to claim 10, wherein the film material is selected from the group consisting of polysulfone, polycarbonate, and polyimide.

TECHNICAL FIELD The present invention relates generally to electroacoustic transducers with diaphragms and blanks for diaphragms, and more particularly to electroacoustic transformers with substantially planar diaphragms to significantly enhance performance. Concerning blanks for diaphragms and diaphragms.

Technical Background Various types and types of electroacoustic transducers have been proposed to date. Such a transducer is, for example, a loudspeaker or a microphone. Both include a movable diaphragm that interacts with the surrounding atmosphere and generates or is actuated by sound waves. As will be apparent to those skilled in the art, the present invention relates to both of these two types of electroacoustic transducers.
However, for the sake of brevity, only the speaker will be described here.

Due to its conical shape, conventional conical speakers
The resulting sound is distorted. Such distortion is known as the "indentation effect." Sound propagated from a speaker cone does not radiate uniformly from its surface. This is because the sound waves emitted from the central portion of the cone are out of phase with the sound waves emitted from the peripheral portions of the cone. The latter sound waves have a shorter distance to travel from the diaphragm to the listener's ears than the sound waves emitted from the central part of the cone.

Various speaker structures have been proposed in the past, some of which have been designed in ways that attempt to overcome this problem. For example, US Pat. No. 3,164,686, 3,171,904,
Reference may be made to Nos. 3922504, 3939312, 3997739, 4056697 and 4276449.

U.S. Pat. No. 3,171,904 eliminates distortion by providing a speaker diaphragm with a substantially planar or flat surface such that the entire surface moves in a vibratory manner by substantially the same distance during use. A speaker having a diaphragm configured with this in mind is disclosed. In this patent, an attempt was made to bring substantially all of the sound waves coming out of the loudspeaker into phase with each other, thereby reducing distortion.

The speaker diaphragm described in US Pat. No. 3,171,904 is constructed from expanded polystyrene to be relatively lightweight. However, such materials do not have sufficient stiffness, so their high frequency response is quite unsatisfactory in many applications.

An electrical voice coil is embedded in the expanded polystyrene diaphragm to cooperate with the magnetic field. The diaphragm is in the form of a solid block of polystyrene with a series of grooves or slots formed therein to define a series of projections, each of which has a voice coil conductor at its tip. This conductor cooperates with the magnet assembly to excite the diaphragm. However, in order to reduce the weight of the diaphragm to an acceptable level and to allow for the attachment of appropriate attachments, only one voice coil conductor is provided on each projection. However, such a single conductor does not provide sufficient efficiency or sufficient resistance characteristics for certain applications.
Also, since there is little space for additional conductors in such a structure, it is difficult, if not impossible, to add additional conductors. Moreover, such structures are very expensive to manufacture.

In order to obtain a good high frequency response, in the case of the speaker diaphragm disclosed in U.S. Pat. No. 3,171,904, a certain given It would be necessary to provide a much larger number of conductors in the area. By the way, the current industry standard resistance value is 4.
~8Ω.

Alternatively, the diaphragm of the above patent may be connected in series with a number of other similarly sized diaphragm units to provide sufficient electrical resistance to obtain the desired impedance. However, such a configuration is highly unsatisfactory in many applications. This is because the number of speaker diaphragms connected in series becomes unacceptably large. The only alternative in this case would be to connect a resistor in electrical series with the voice coil to set the proper resistance. However, such solutions are usually not preferred. This is because the resistor simply dissipates the electrical signal without using it, and therefore such speakers do not operate very efficiently. Also, when resistors are connected in series, 1
If one diaphragm unit fails, the entire unit will malfunction. Additionally, additional diaphragms connected in series would significantly increase the bulk, size and weight of the loudspeaker system, thus making such a configuration prohibitive for most applications. It is extremely unsatisfactory for many applications.

On the other hand, perhaps the most significant disadvantage of using expanded polystyrene as described above is the inherent spongy, non-rigid nature of the material. Such materials are not useful for high frequency conduction.

U.S. Pat. No. 4,276,449 discloses a transducer diaphragm constructed by folding a thin sheet of film material into an elongated arcuate corrugated sheet. Current-carrying conductors are disposed on both sides of the film and are disposed in the valleys of the bent film diaphragm so as to extend between spaced apart permanent magnet bars.

However, the series of elongated top portions of this diaphragm renders the front surface uneven. Such a diaphragm is therefore capable of achieving the desired effect of bringing substantially all of the sound waves emanating from it into phase with each other for the purpose of significantly reducing or eliminating distortion of the sound waves. Can not.

Also, the elongated peaks and valleys, except for the edges of the folded film, are bonded or otherwise supported, creating a weak structure. Therefore, the valley and its associated conductor are not rigidly positioned in alignment with the magnetic structure. the result,
When the diaphragm moves rapidly relative to the magnetic bar, the valleys can move laterally, and therefore, in some applications, the current-carrying conductors in the troughs of the diaphragm and the magnetic bar may move sideways. The desired precise magnetic interaction cannot be obtained between the two.

Furthermore, since these conductors are arranged out of phase with each other on both sides of the film, when the thin film is folded, it is prone to buckling or arching; Proper alignment of each conductor with respect to the gap between the magnetic bars is not achieved.

Accordingly, it would be highly desirable to provide an electroacoustic transducer having a diaphragm that significantly reduces, if not minimizes, speaker distortion when used as a speaker, yet has a high operating efficiency. In addition, the diaphragm is sufficiently lightweight,
In addition, it must have a capacity to accommodate a sufficient number of voice coil conductors to obtain good impedance characteristics.

Such a diaphragm must be substantially rigid so that it can maintain its conductors in proper alignment with the magnetic structure during use, and must be relatively inexpensive to manufacture. It won't happen.

DISCLOSURE OF THE INVENTION Accordingly, a principal object of the present invention is to provide a new and improved electroacoustic transducer and diaphragm that significantly reduces transducer distortion and achieves accurate reproduction with efficient operation. The aim is to provide a blank for

Another object of the invention is that the invention is relatively lightweight and yet
An object of the present invention is to provide an electroacoustic transducer with a diaphragm that can accommodate a large number of conductors, is inexpensive to manufacture, and is structurally robust, and a blank for such a diaphragm.

Briefly, the above and other objects of the present invention are to provide an electroacoustic transducer with a movable diaphragm in generally planar form and a blank for such a diaphragm. will be achieved.

The transducer diaphragm consists of a thin folded sheet of material having a front surface and a plurality of rearwardly projecting protrusions in the form of fins or vanes. Each protrusion is provided with at least one conductor portion. A thin, substantially flat support sheet is affixed to the folded sheet to form the front face of the diaphragm and to stiffen the folded sheet. In a preferred embodiment of the present invention, each of the protrusions is generally groove-shaped over its entire length and consists of a pair of side portions and a central portion interconnecting the side portions.

In one embodiment of the invention, at least one section of conductor is arranged on each protrusion. The diaphragm is formed from a blank consisting of a sheet of film material having a pair of similar conductors. This one
The pair of conductors are formed in a similar shape and are arranged on both sides of the film material sheet so as to face each other and align with each other, and the blank, which has not yet been bent, has a stable shape. The diaphragm does not curl or warp due to the stress imposed by the conductors, and therefore can be easily bent to allow the diaphragm to bend without bowing or other deformation. can be formed.

Also, by using a lightweight film material, a much larger number of conductors can be easily placed to increase usage efficiency compared to conventional diaphragms. Thus, the diaphragm of the present invention is made of a lightweight material and can accommodate a large number of conductor sections, providing a highly desirable response. In order to enable the diaphragm blank to remain flat when not bent, a plurality of conductor sections are provided on both the inner and outer surfaces of each protrusion of the diaphragm. If the transducer is a dynamic speaker, it is preferred to provide multiple paths of the conductor portion to the assembly in use.

The lightweight, flat diaphragm of the present invention functions as a heat pump by forcing air to flow around the conductors to cool the diaphragm unit during use. Heat build-up is one of the leading causes of failure in conventional speakers. This is because the heat causes the voice coil conductor to separate from the bobbin attached to the cone of the diaphragm. Incidentally, the adhesive often melts as a result of temperature rise, especially if the loudspeaker is overexcited primarily due to lack of sufficient air circulation. In contrast, in the speaker of the present invention, air is passed past the conductor for cooling purposes and exhausted through the gap in the magnet assembly, so that every time the diaphragm vibrates, air is passed for cooling purposes. Therefore, it is sucked into and out of the space around the conductor. Therefore, the more intensely the diaphragm is excited, the more heat is removed from the unit by the vibrations of the diaphragm itself.

The diaphragm also cooperates electromagnetically with permanent magnets uniformly distributed around its back surface, allowing for a uniform response. A speaker using the diaphragm of the present invention is a full frequency range speaker.

When the diaphragm of the present invention is used in a speaker, its lightweight structure and large number of current-carrying conductors combine to provide excellent response at high frequencies. Additionally, the grooved shape of the diaphragm projections, together with the support sheet affixed thereto, provide suitable structural reinforcement for the diaphragm, and the series of spaced apart conductor-carrying projections can be assembled into a magnet assembly. Helps maintain accurate alignment between the pole pieces of the permanent magnet.

[Brief explanation of drawings]

The above and other objects and features of the invention;
and the manner in which they are achieved will become clear from the description below. Further, the content of the present invention will become clear from the description of the embodiments described below with reference to the accompanying drawings.

FIG. 1 is a partial cross-sectional view of an electroacoustic transducer as a speaker constructed in accordance with the present invention.

FIG. 2 is an enlarged partial cross-sectional view of a portion of the diaphragm of the speaker of FIG. 1, showing the diaphragm positioned within the gap of the excitation magnet assembly.

FIG. 3 is a perspective view of the speaker diaphragm of FIG. 1, showing the bottom surface of the diaphragm.

FIG. 4 is an enlarged elevational view, partially in section, of the end portion of the diaphragm of FIG. 3. FIG.

FIG. 5 is a partial schematic front view of the film blank of the diaphragm of FIG. 3 prior to final bending, with a portion of the blank cut away and the conductors schematically drawn by lines for illustration purposes; It is shown.

FIG. 6 is a perspective view of a portion of an electroacoustic diaphragm of another embodiment constructed in accordance with the present invention and having a corrugated top connected to a protrusion.

FIG. 7 is an elevational sectional view of a portion of yet another embodiment of an electroacoustic diaphragm constructed in accordance with the present invention.

FIG. 8 is a perspective view, partially in section, of a portion of yet another embodiment of an electroacoustic diaphragm constructed in accordance with the present invention.

FIG. 9 is a perspective view, partially in section, of a portion of yet another embodiment of an electroacoustic diaphragm constructed in accordance with the present invention.

MODES FOR CARRYING OUT THE INVENTION Referring now to the accompanying drawings, and in particular to FIGS. 1, 2 and 3, there is shown an electroacoustic transducer in the form of a dynamic speaker 10 constructed in accordance with the present invention. There is.

Speaker 10 generally consists of a rectangular diaphragm or membrane 12 that cooperates electromagnetically with a series of pole piece gaps 13 of magnet assembly 14 (FIG. 1).

The diaphragm 12 is movably supported by a housing or a baffle frame 16 at the front of the magnet assembly 14 so as to cross an opening 17 thereof. For this purpose, a pair of flexible hemming (suspension) strips 18, 20 are provided on the diaphragm 1.
2 and extending laterally longitudinally from the side edges, a pair of elongated gasket strips 22, 24 are connected at their side edges to corresponding border strips 18, 20, respectively; Moreover, it is connected to the frame 16. Each gasket strip includes a series of integral, spaced apart tab ears 22.
A, 24A is provided. These ear pieces are attached to the gasket strip 2 when assembling the speaker 10.
2, 24, and thus the diaphragm and each projection P relative to the respective gap of the magnet assembly installed in the exciter frame 16 behind the opening 17. As shown in FIG. 3, a pair of flexible spider-type connector strips 26, 28 extend laterally from opposite edges of diaphragm 12 and connect those edges to a pair of generally rectangular connector strips 26, 28. They are connected to end mounting blocks 31 and 33, respectively. The blocks 31, 33 are adapted to be attachable to the frame 16 at their openings 17.

As clearly shown in FIG. 1, the front surface 29 of the folded sheet 34A integrally interconnects a series of spaced parallel, rearward, extended conductor-bearing protrusions P; It is formed by a series of flat portions 30 lying approximately in a common plane. The conductor supporting protrusion P is connected to the permanent magnet assembly 14
magnetically interact with the diaphragm 12 to vibrate the diaphragm 12 to generate desired sound waves.

The interconnecting portions 30 are arranged transversely to the longitudinal axis of the projection P at an angle of substantially 90°. A support sheet 32 in the form of a thin film sheet is placed over and fixed to the interconnecting parts 30 and stiffens each projection P and the overall structure of the diaphragm 12. The front surface of the seat 32 also provides a substantially smooth, planar surface for the diaphragm 12 so that it can function over the entire frequency range with little distortion.

The sheet 32 includes a sheet 34A and its protrusion P.
The seat 34A is attached to the interconnecting portion 30 of the sheet 34A, which provides a substantial mounting surface area so that it can be rigidly attached to the seat 34A. Thus, sheet 32 remains substantially flat during use and exhibits the desired frequency response characteristics.

As shown in FIG.
Figure 3) consists of a blank 34 that generally includes a rectangular sheet 34A of thin film material and is in a substantially flat configuration before being folded. Assembly of the diaphragm 12 involves folding the blank 34 to form a series of parallel, spaced apart, longitudinally extending protrusions P in the form of vanes or fins 35. Each vane or fin 35
is elongated, groove-shaped, and has a generally U-shaped cross-sectional shape over its entire length. The vane or fin 35 is
It projects rearward toward the magnet assembly 14.

As shown in FIG.
A series of inner voice coil conductor sections, such as 7 and 38, are attached to one side of the film blank 34 and are located on the inner side of the vane, such as vane 35. The other side of the film blank 34 (FIG. 5) has corresponding conductor portions 36, 3, respectively.
7, 38 to align with the conductor portions 39, 40,
A series of outer voice coil conductor sections, such as 41, are attached and disposed on the outer surface of the vane, such as vane 35.

As shown in FIGS. 1 and 2, magnet assembly 14 generally consists of a series of magnets 42 arranged side by side. The magnets 42 each have their N
It is a permanent magnet with poles and south poles oriented as shown. As shown in FIG. 1, adjacent portions of each magnet have the same polarity. Each of these excitation magnets has on each side a pair of elongated steel pole pieces, such as pole pieces 44, 46, placed on either side of the permanent magnet 42, with a space between the pole pieces. It is adapted to define a series of parallel spaced gaps 47 for receiving the vanes 35 of the diaphragm 12.

In use, as a result of the dynamic electromagnetic interaction between the current-carrying conductor portions on the vanes 35 and the pole pieces of the permanent magnets, the diaphragm 12 vibrates so that the vanes 35 move longitudinally within the pole piece gaps 47. Exercise.
The same oscillatory movement of the vanes 35 and the supporting sheet 32 attached thereto forces air into the gaps 47 for cooling purposes.
, thereby reducing heat build-up. The stronger the diaphragm is vibrated, the greater the pumping action of the diaphragm, and the more air it expels for cooling. Such an increase in air flow is
As the diaphragm is vibrated violently, heat build-up increases, especially if it is excited beyond the desired limits.
desirable. Additionally, increased air flow is desirable in certain applications (eg, automotive) due to high ambient temperatures.

Referring to FIG. 1, a pair of gasket strip clamping plates 4 are used to attach the border strips 18, 20 to the exciter frame 16.
8 and 51 are each gasket strip 2
2 and 24 to the frame 16, and screws 53 and 5.
5 fastens the fastening plate to the frame 16. As shown in FIG.
Screw receiving notches 5 provided in 1 and 33 respectively
7, 59, attach those mounting blocks to frame 1.
6 for receiving mounting screws (not shown) for fastening to the screws.

As clearly shown in FIG. 2, each protrusion P is
It has a pair of side parts 60, 61 and a central part 62 which interconnects them at the rear end.
The side portions are transverse to the central portion 62,
arranged substantially at right angles. The inner conductor 37 and the outer conductor 40 are arranged directly opposite each other on both sides of the central portion 62. conductors 38 and 4
1 are arranged opposite to each other on both sides of the side part 60, and conductors 36 and 39 are arranged opposite to each other on both sides of the side part 61.

Film blank 34 will be described in more detail with reference to FIG. 5. Blank 34 is generally formed of any suitable high temperature class thermoplastic blend material. Preferred materials include polysulfones, such as those sold under the trademark "UDEL" by Union Carbide Company of Danbury, Conn. Other suitable compounds include ``ULTEM'' manufactured by General Electric Company;
"POLYETHER SULFONE" sold by Industries, Inc.
sulfone) and "RADEL" (polyphenylsulfone) sold by Union Carbide. In addition, "LEXAN" sold by General Electric Company
Suitable polycarbonates can also be used, such as. Polyimide can also be used.

In general, high temperature thermoplastic materials not only have relatively high heat deflection temperatures, but also have relatively high glass transition temperatures. Sheet 34A is annealed and formed into the desired shape, but not during high temperature operation and at high ambient temperatures, such as when the speaker is used in an enclosed automobile parked in the sun. In order to maintain the desired shape of the sheet 34A, when polysulfone "UDEL" is used as the material for the sheet 34A, the annealing temperature is preferably in the range of about 300 to 375, preferably about 330. It should be 〓. Although materials with lower annealing temperatures may also be satisfactorily used, the temperature ranges mentioned above are preferred;
For other materials, temperatures higher than the above temperature range are preferred. Sheet 34A has a thickness of approximately 3 mils and the conductors are approximately 1 mil thick.

The sheet 34A has a conductive pattern 67 attached to its front surface and electrically connecting a pair of terminals 63 and 65. A similar conductor pattern 67A, which is a mirror image of the conductor pattern 67 on the front surface, is adhered to the back surface of the sheet 34A so as to face and align with the conductor pattern 67. Thus, the sheet 34A has a greater tendency to remain flat and less likely to warp, making it easier to manipulate and bend it into the desired shape.
It also facilitates storage of the blank 34. If the sheet 34A is folded as shown in FIGS. 1 and 3 along each longitudinal conductor attached thereto, the folded sheet 34A will have little or no arching from one end to the other. The desired shape is achieved without warping. It has been found that if the two conductor patterns on the front and back surfaces are not placed in alignment with each other, the folded sheet will arch or otherwise warp from one end to the other. There is.

Conductor patterns 67 and 67A are electrically connected in parallel. That is, the terminals 63 and 65 of the conductive pattern 67 on the front surface of the sheet 34A and the
It is electrically connected to a corresponding terminal (not shown) of the conductor pattern 67A on the rear surface of A. Fourth
As shown in the figure, the terminal wire 63A is soldered to the terminal 63 and the corresponding terminal on the back surface of the sheet 34A. This is because the ends or eyelets (not shown) of solder and wire 63A extend through the holes in sheet 34A. Similarly, the terminal wire 65A connects the terminal 65 of the conductor pattern 67 and the conductor pattern 6.
It is electrically connected to the corresponding terminal of 7A.

The conductor pattern 67 is a so-called "Greek pattern" and has a transversely extending conductor portion 69 that is integrally electrically connected to the terminal 63 at one end and connected to the longitudinally extending conductor 41 at the other end. . Here, what is the "Greek pattern"?
As shown in Figure 5, relatively long straight lines extending parallel to each other at intervals (conductors here)
A meandering or zigzag pattern consisting of a relatively short straight line in the transverse direction extending at right angles to the long straight lines and connecting the ends of the long straight lines. The conductor 41 is integrally articulated with an outer transversely extending conductor portion 72 . Transverse extension conductor portion 72
A longitudinally extending conductor portion 74 extends from the transversely extending conductor portion 76 . Thus, part 4
1, 72, 74 constitute one U-shaped part of the pattern 67.

Similarly, the longitudinally extending conductor section 78 is connected to the transversely extending conductor section 76 and the transversely extending conductor section 8.
1 to complete another U-shaped section consisting of sections 74, 76, and 78. The longitudinally extending conductor section 83 extends between the transversely extending conductor section 81 and the transversely extending conductor section 85 and is configured to form a U-shape with the sections 78, 81, and 83.

A longitudinally extending conductor section 87 connects the transversely extending conductor section 85 and the long transversely extending conductor section, the latter integrally articulated with a longitudinally extending conductor section 92 disposed near its edge. . A transversely extending conductor portion 94 connects conductor portion 92 and longitudinally extending intermediate conductor portion 40 . part 8
3, 85, 87 also define a U-shape.

Conductor section 40 connects a transversely extending conductor section 94 to another transversely extending conductor section 98 .
Portion 98 extends parallel to portion 72, the latter of which includes portion 98 and a long transversely extending conductor portion 89.
It is located between.

A longitudinally extending conductor section 101 extends between transversely extending conductor section 98 and transversely extending conductor section 103 . Portion 101 extends parallel to portion 74 and portion 103 extends parallel to portion 76. Longitudinal extension portion 105 extends from portion 103
and a transversely extending conductor section 107, the latter lying parallel to section 81.

A longitudinally extending conductor section 109 is located parallel to section 83 and connects section 107 and transversely extending conductor section 112 . Part 109 is part 8
3 and section 112 extends parallel to section 85.

A longitudinally extending conductor section 114 extends parallel to section 87 and connects section 112 with a shorter transversely extending conductor section 116. A longitudinally extending conductor section 118 connects section 116 and a long transversely extending conductor section 121. Portion 118 is located near the left edge of blank 34 and portion 121 extends parallel to the bottom edge of the blank.

Conductor 39 is longitudinally extending and extends between longitudinally extending conductor portion 121 and short transversely extending conductor portion 135 . A longitudinally extending conductor section 137 connects section 135 and a short connecting section 139 that connects to terminal 65 .

Blank 3 as shown in Figures 3 and 4.
4 is bent in the longitudinal direction to form a series of folds, thereby forming a series of protrusions P. A pair of end plates 142, 14 are provided to stiffen the diaphragm.
4 to the folded blank 34 by any suitable technique, such as by heat sheeting or by applying adhesive or solvent. 1st
and a folded blank 34, as shown in FIG.
A support sheet 32 is secured over the front surface 29 formed by the connecting portion 30 of the support sheet 32 .

Referring to FIG. 6, it includes a diaphragm 186 constructed in accordance with the present invention and adapted to be excited by a magnet assembly (not shown) of similar construction to the magnet assembly of FIG. Another example acoustic transducer 185 is shown.

Diaphragm 186 is generally similar to the diaphragm of FIG. 1 and includes a series of spaced apart, longitudinally extending projections in the form of vanes or fins, such as vanes 187 and 189. These protrusions are groove-shaped over their entire length and have a U-shaped cross section.

Support sheet 190 is secured by any suitable technique, such as a suitable adhesive or ultrasonic welding, and is adapted to serve the same purpose as support sheet 32. To provide lateral stability to each vane, a series of parallel spaced depending ridges, such as ridges 191, project into the upper portion of each vane, such as vane 186. Sheet 190 is formed from a suitable foam material, such as expanded polystyrene or expanded polysulfone. The foam sheet 190 is a bent film diaphragm 1
It is molded to closely match the outer shape of the front portion of 86.

We will now consider Vane 187 in detail. All of the other vanes are similar to vane 187, so the other vanes will not be described in detail. A series of three outer voice coil conductors 192,1
94, 196 are affixed to the outer surface of vane 187 in a manner similar to the outer voice coil conductors coupled to diaphragm 12, and a series of three inner voice coil conductors 198, 201, 203, each corresponding to Vane 18 opposite the outer voice coil conductor
attached to the inner surface of 7.

To stiffen vane 187 and maintain its stability and position, vane 187 is provided with a series of longitudinally spaced gussets or corrugations, such as gussets 205. These gussets help maintain the longitudinal axis of vane 187 substantially perpendicular to the plane of support sheet 190. The lateral stability of vane 187 is thus enhanced. The vane 187 and the adjacent vane 189 connect the gusset 205 to the vane 189.
are interconnected by an integral web portion 207 having a series of parallel spaced ridges or corrugations, such as ridges or corrugations 209 that connect to gussets 210 in the sidewalls of the web. The gusset 211 provided on the side wall opposite the vane 189 is formed in a complementary relationship with the gusset 210, and is heat-sheeted onto the gusset 210.
Provides structural rigidity to vane 189. The ridges or corrugations 212 of the web portion 207 form the gussets 21
It is connected to 1. Thus, pairs of complementary inwardly projecting gussets (e.g., 210 and 211) are heat-sealed to each other to join the side walls of the vanes to stabilize lateral displacement of each vane. or connected by adhesive.

Referring to FIG. 7, an acoustic transducer 213 constructed in accordance with the present invention and having a diaphragm 213A is shown. The diaphragm 213A is substantially the same as the diaphragm 186 of FIG. 6, except for its stiffening aspect.

The diaphragm 213A is groove-shaped over its entire length and has a series of parallel spaced apart elongated protrusions in the form of vanes or fins, such as vanes 214 having a U-shaped cross-section. A series of five spaced apart outer conductors, such as outer conductors 215 and 216, are disposed in the bottom portion of the vane 214, and an inner conductor 2
A series of four parallel spaced inner conductors, such as 17 and 218, are arranged in opposing alignment with corresponding outer conductors 215 and 216, respectively.

A flat support sheet 219 is fixed to the remaining portion of the diaphragm 213A in the same manner as the support sheet 32 fixed to the front portion of the diaphragm 12. A series of spaced pairs of gussets, such as gussets 221 and 221A, are disposed on vane 214 in a manner similar to the gussets of diaphragm 186 and are heat-sealed together. However, the gussets in this embodiment do not extend into the upper web portion as in the case of web portion 207 of diaphragm 186.

Referring to FIG. 8, the magnet assembly 14 of FIG.
An acoustic transducer 225 according to another embodiment of the present invention is shown with a diaphragm 225A excited by a magnet assembly (not shown) similar to . This diaphragm 225A is substantially similar to diaphragm 186, except for its support sheet, and includes a series of parallel spaced apart U-shaped vanes, such as vanes 222, 223. Here vane 22
2 will be explained in detail, the vane 223 is also the same as the vane 222. Attached to the bottom outer surface of vane 222 is a series of three outer current-carrying conductors 224, 226, 230 in a manner similar to the outer conductors attached to vane 35 of FIG. The inner surface includes a series of three parallel spaced inner current-carrying conductors 232, 233,
237 are attached opposite to the respective outer conductors.

A support member 239 is attached to this diaphragm in the same manner as the support member 32 fixed to the diaphragm in FIG. Support member 239 is formed of a film material similar to that of FIG. 1 and extends from the vane in a manner similar to the depending ridges 191 of film support member 190 projecting into the interior space of vane 187 in FIG. It includes a series of depending channels 240 that partially extend into the interior space.

Referring to FIG. 9, the magnet assembly 14 of FIG.
An acoustic transducer according to another embodiment of the present invention is shown having a diaphragm 241 adapted to be excited by a magnet assembly (not shown) similar to . Diaphragm 241 is generally similar to diaphragm 186 of FIG. 6, except that it does not have gussets and includes a series of parallel spaced apart elongated U-shaped vanes, such as vanes 243 and 244. It is equipped with

Since vane 244 is the same as vane 243, considering vane 243 now, vane 243 consists of a series of three outer current-carrying conductors 245, 247, arranged around the outer circumferential surface of its bottom portion.
It is equipped with 249. The inner surface of the vane 243 includes a series of three inner conductors 250, 252, 25.
4 are arranged in opposing alignment with the respective outer conductors.

A foam support sheet 258 is secured in place in a manner similar to film support sheet 190. The support sheet 258 has vanes 2
43, 244 are provided, such as a series of elongated depending ridges 261, 263 projecting into the interior upper portion of the vane. Ridges 261, 26
3 performs the same function as the channel 240 of the diaphragm 225A.

Although specific embodiments of the invention have been disclosed, it will be appreciated that various modifications may be made within the spirit and scope of the claims. for example,
A variety of different types and types of materials can be used as the material for the diaphragm of the present invention.
Therefore, the invention is not strictly limited to the above description.