JP2005073129A - Speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a miniaturized speaker suitable for cellular phone etc. having excellent acoustic characteristics. <P>SOLUTION: A diaphragm unit 20 is received in a case 10 and a back cavity 70 is formed on the rear side thereof. A diaphragm body 21 of the diaphragm unit 20 and an edge part 22 on the peripheral side of the body 21 for supporting the diaphragm body 21 are constructed of different materials. According to this construction, the lowest resonance frequency (f0) decreases and the reproduction frequency band is increased. A dome-like curved part 25 in the edge part 22 is convex in the direction of front side and has a tapered shape so that the thickness thereof decreases gradually from the peripheral part toward inside. According to this shape, the stress applied to the edge part 22 when the diaphragm body 21 vibrates is efficiently distributed to make the amplitude large with low distortion. The back cavity 70 communicates with the outside of the case via a long channel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a speaker suitable for a small speaker used in a mobile phone or the like.

In a small speaker used for a cellular phone or the like, there is an essential problem that the lowest resonance frequency (f ₀ ) becomes high, and as a result, the reproduction frequency band becomes narrow. As one effective means for solving this problem, it has been proposed to change the constituent materials of the diaphragm main body and the edge of the diaphragm unit (see Patent Document 1 and Patent Document 2).

Japanese Patent No. 3158023 Japanese Unexamined Patent Publication No. 7-15793

That is, the diaphragm unit is usually composed of a diaphragm main body part and an annular edge part located on the outer peripheral side thereof, and the edge part protrudes in a convex direction toward the front side in order to elastically support the diaphragm main body part. It is customarily formed in a curved dome shape. Conventionally, the diaphragm main body and the edge were made of the same material (polyethylene terephthalate, etc.), so that the rigidity of the edge became too high and the movement of the diaphragm main body tended to be hindered. The advantage is that the lowest resonance frequency (f ₀ ) is lowered and the reproduction frequency band is widened by forming the edge part with a material softer than the material constituting the diaphragm main body and integrating it with the diaphragm main body. Is obtained.

  However, as a recent trend in mobile phones and the like, the level required for sound quality has become very high. For this reason, development of materials and the like has been promoted, but it is not sufficient.

  An object of the present invention is to provide a speaker capable of ensuring excellent sound quality even in a small size.

  In order to achieve the above object, a speaker according to the present invention has a diaphragm unit in which an annular edge portion made of a material softer than the main body portion is joined and integrated to the outer peripheral portion of the diaphragm main body portion. The edge portion is formed in a dome shape curved in a convex direction toward the front side, and the dome-shaped curved portion is formed in a tapered shape having a thickness gradually decreasing from the outer peripheral portion toward the inner peripheral portion.

In the speaker according to the present invention, the diaphragm main body portion and the edge portion are made of different materials and integrated, so that the lowest resonance frequency (f ₀ ) is lowered and the reproduction frequency band is widened. Moreover, since the dome-shaped curved portion of the edge portion is formed in a tapered shape with the thickness gradually decreasing from the outer peripheral portion toward the inner peripheral portion, the stress applied to the edge portion when the diaphragm body vibrates is efficient. Disperse well. As a result, the amplitude increases with low distortion.

  Silicon is preferable as the material constituting the edge portion. In this case, as a material constituting the diaphragm main body, polycarbonate (PC), polyethylene terephthalate (PET), polyetherimide (PEI), or polycarbonate / polycarbonate (PC) having higher rigidity than silicon and good adhesion affinity with silicon. Polybutylene terephthalate (PC / PBT) is preferred.

  Silicon is effective in improving sound quality, but it is inherently poor in adhesion. When the voice coil is bonded to the back side of the outer periphery of the diaphragm main body, the voice coil may have to be bonded to the edge if the edge is located on the back side at the joint between the diaphragm main body and the edge. is there. When the diaphragm body is overlapped on the back side of the edge part at the joint between the diaphragm body part and the edge part, when the voice coil is adhered to the back side of the diaphragm body part, the voice coil is adhered to the diaphragm body part. It becomes possible to secure good adhesion.

In the case of a small speaker incorporated in a mobile phone, it is rarely accommodated in a dedicated case, and it is usual to form a back cavity on the back side using the device case in a state of being incorporated in the device. In that case, the capacity of the back cavity changes depending on the structure of the device, and there are many cases where normal acoustic characteristics cannot be obtained. By accommodating the diaphragm unit in a dedicated case and forming a back cavity on the back side, the sound quality is stabilized without being affected by the structure of the device. Since the lowest resonance frequency (f ₀ ) is low, it can be driven even if the back surface capacitance is small, and the downsizing of the device is not hindered.

  When a back cavity is formed using a special case, if the cavity is sealed, the characteristics may change due to changes in atmospheric pressure or temperature, and the diaphragm unit may be damaged. For this reason, it is effective to communicate the back cavity outside the case. However, if there is only a simple air hole, the cavity will come out due to communication with the outside of the case. By adopting a structure in which the back cavity communicates with the outside of the case through a long groove formed in the case, the long groove functions as a resistor that prevents the back cavity from coming off, and the acoustic characteristics are stabilized.

  Regarding electrical connection between the speaker and the device side, it is preferable to use a spring terminal that presses against the device side when the speaker is incorporated into the device. Solderless connection is possible, reducing the environmental burden.

  In the speaker according to the present invention, the diaphragm main body portion and the edge portion are made of different materials and integrated, and the thickness of the dome-shaped curved portion of the edge portion gradually decreases from the outer peripheral portion toward the inner peripheral portion. By forming the taper shape, the amplitude can be increased with low distortion, and excellent sound quality can be secured even in a small size.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a perspective view showing the appearance of a speaker according to an embodiment of the present invention from the front side, FIG. 2 is a perspective view showing the appearance of the speaker from the back side, and FIG. 3 is a longitudinal side view of the speaker in FIG. FIG. 4 is a perspective view showing the rear frame constituting the speaker case from the inner surface side, FIG. 5 is a perspective view showing the front frame constituting the case from the inner surface side, and FIG. FIG. 7 is a longitudinal sectional view showing a spring terminal portion of the speaker, FIG. 7 is a longitudinal sectional view of a diaphragm unit used in the speaker, and FIG. 8 is a longitudinal sectional view showing a manufacturing method of the diaphragm unit.

  The speaker according to the present embodiment is a small speaker used for a mobile phone. As shown in FIGS. 1 to 3, this small speaker drives a horizontally long case 10 corresponding to the shape of the speaker portion of the mobile phone, a diaphragm unit 20 accommodated in the case 10, and the diaphragm unit 20. An annular voice coil 30 adhered to the back surface of the diaphragm unit 20 and a magnet unit disposed on the back side of the diaphragm unit 20 to drive the diaphragm unit 20 in cooperation with the voice coil 30 40 and spring terminals 50 and 50 attached to the case 10 for electrical connection with a mobile phone.

  The case 10 is composed of a horizontally long saucer-shaped rear frame 10A and a cap-shaped front frame 10B covering the same. The front edge of the rear frame 10A is gently curved corresponding to the shape of the speaker portion of the mobile phone. As shown in FIG. 4, projections 11 and 11 for attachment are provided on the front edge portion. A long groove 12 having one end opened and the other end closed is provided along the front edge. Although described in detail later, the long groove 12 functions as a resistor for preventing the back cavity formed in the case 10 from coming off.

  Recesses 13 and 13 for attachment are provided at the linear rear edge of the rear frame 10A. Further, terminal holes 14, 14 through which the spring terminals 50, 50 pass are provided inside the recesses 13, 13.

  The front edge of the front frame 10B is gently curved corresponding to the rear frame 10A. As shown in FIG. 5, the front frame 10 </ b> B is provided with a circular mounting hole 15 that accommodates the diaphragm unit 20 and the magnet unit 30 in the center portion. A plurality of holding portions 16, 16... Holding the magnet unit 30 are provided on the inner peripheral surface of the mounting hole 15 with a gap in the circumferential direction.

  At the front edge of the front frame 10B, a lid 12 'for closing the long groove 12 is provided along the front edge, and a vent hole 17 is provided at the closed end of the long groove 12 (FIG. 1). reference). The vent hole 17 is a hole that allows the back cavity formed in the case 10 to communicate with the outside of the case. On the straight rear edge of the front frame 10B, mounting recesses 13 'and 13' corresponding to the mounting recesses 13 and 13 are provided. Further, circular concave portions 14 ′ and 14 ′ into which the head portions of the spring terminals 50 and 50 are inserted are provided corresponding to the terminal holes 14 and 14.

  As shown in FIG. 6, the spring terminal 50 is a two-stage coil spring in which a large-diameter head portion 51 and a small-diameter contact portion 52 are combined. The concave portion 14 ′ provided in the front frame 10 </ b> B has a larger diameter than the head portion 51. The terminal hole 14 provided in the rear frame 10 </ b> A has a two-stage structure in which the front side has a larger diameter than the head part 51 and the back side has a smaller diameter than the head part 51 and a larger diameter than the contact part 52.

  The spring terminal 50 is held in the case 10 by combining the rear frame 10A and the front frame 10B in a state where the spring terminal 50 is passed through the terminal hole 14. That is, by combining the rear frame 10 </ b> A and the front frame 10 </ b> B, the large-diameter head portion 51 of the spring terminal 50 is compressed between the frames and held in the case 10. In addition, the large-diameter head portion 51 is pressed against a terminal plate 53 that is insert-molded in the front frame 10B, and the small-diameter contact portion 52 elastically protrudes from the terminal hole 14 to the rear side of the rear frame 10A.

  As shown in FIG. 7, the diaphragm unit 20 accommodated in the case 10 includes a thin disk-shaped diaphragm main body portion 21 and an annular edge portion 22 made of silicon resin joined to the outer peripheral portion thereof. . Since the edge portion 22 is made of silicon resin, the diaphragm main body portion 21 has a higher rigidity than the silicon resin and has good adhesion affinity with the silicon resin. PEI) or polycarbonate / polybutylene terephthalate (PC / PBT).

  The diaphragm main body portion 21 has a center dome shape in which a portion excluding the outer joint portion 23 is formed in a dome shape convex toward the front side. In order to enhance the vibration characteristics of the diaphragm main body 21, the silicon resin edge portion 22 is formed in a direction convex to the front side between the inner peripheral flat joint portion 23 and the outer peripheral thick holding portion 24. It has an annular dome-shaped curved portion 25 that is curved. The dome-shaped curved portion 25 is formed in a tapered shape whose thickness gradually decreases from the outer peripheral portion toward the inner peripheral portion. In the joint portion 23 between the diaphragm main body portion 21 and the edge portion 22, both are joined and integrated by fusion, and the diaphragm main body portion 21 overlaps the back side of the edge portion 22.

  As shown in FIG. 3, the thick retaining portion 24 formed on the outer peripheral portion of the edge portion 22 is fitted into an annular recess 18 provided around the mounting hole 15 on the front surface of the front frame 10B. doing. Thereby, the diaphragm unit 20 is held in the mounting hole 15 of the front frame 10B. A back cavity 70 is formed in the case 10 by mounting the diaphragm unit 20 in the mounting hole 15 of the front frame 10B.

  A baffle 60 is fitted into the mounting hole 15 of the front frame 10B from the front side. The baffle 60 is attracted and held in the mounting hole 15 by a magnet unit 30 described later. Thereby, the baffle 60 protects the diaphragm unit 20 and fixes the holding portion 24 to the annular recess 18. The baffle 60 is provided with a plurality of sound emission holes 61.

  The annular voice coil 30 is bonded to the back surface of the diaphragm unit 20, and more specifically, is bonded to the joint portion 23 of the diaphragm main body portion 21 from the back surface side with a thinner adhesive. Each terminal of the voice coil 30 is connected to a terminal plate 53 that is insert-molded in the front frame 10B.

  A magnet unit 40 disposed on the back side of the diaphragm unit 20 together with the voice coil 30 includes a yoke 41 formed in a circular tray shape, a disk-shaped magnet body 42 joined to the center of the surface of the yoke 41, and And a circular electrode plate 43 bonded to the surface thereof. And the magnet unit 40 is fixed to the back surface side of the diaphragm unit 20 by pushing the peripheral wall portion of the yoke 41 into the mounting hole 15 of the front frame 10B from the back surface side and fixing with the plurality of holding portions 16, 16,. Yes.

  The voice coil 30 disposed on the back side of the diaphragm unit 20 together with the magnet unit 40 is inserted into an annular gap formed along the inner surface of the peripheral wall portion of the yoke 41, so that interference with the magnet unit 40 is prevented. Avoided.

  The diaphragm unit 20 is manufactured as follows.

  As shown in FIG. 8, a circular resin plate to be the diaphragm main body 21 is sandwiched and heated between the lower mold 80A and the upper mold 80B. As a result, the resin plate is thermoformed on the diaphragm main body 21. Simultaneously with this heat forming, silicon resin is injected into a cavity formed between the lower mold 80A and the upper mold 80B on the outer peripheral side of the diaphragm main body 21, and the edge 22 is injection molded. The injection-molded edge portion 22 is fused to the outer peripheral portion of the diaphragm main body portion 21.

  Next, functional features of the speaker according to this embodiment will be described.

Since the edge portion 22 of the diaphragm unit 20 is made of a silicon resin that is more flexible than the diaphragm main body 21, the lowest resonance frequency (f ₀ ) is lowered and the reproduction frequency band is widened. In addition, since the dome-shaped curved portion 25 of the edge portion 22 is formed in a tapered shape whose thickness gradually decreases from the outer peripheral portion toward the inner peripheral portion, it is added to the edge portion 22 when the diaphragm main body portion 21 vibrates. The stress is dispersed efficiently. As a result, the amplitude increases with low distortion.

  The thickness ratio of the dome-shaped curved portion 25, that is, the ratio of the minimum thickness to the maximum thickness is preferably 10: 7 to 10: 5. When this ratio is close to 1, a predetermined effect cannot be obtained sufficiently. If the thickness is too small, the acoustic characteristics deteriorate on the contrary because of the harmful effect that the minimum thickness portion becomes too thin or the maximum thickness portion becomes too thick.

  The voice coil 30 is bonded to the back surface of the joint portion 23 between the diaphragm main body portion 21 and the edge portion 22 with a thinner adhesive. Silicone resin does not have good adhesion with a thinner-based adhesive, but the edge portion 22 is located on the front surface side and the diaphragm main body portion 21 or the rear surface side at the joint portion 23, and A voice coil 30 is bonded to the rear surface of the outer peripheral portion. Since the diaphragm main body 21 has better adhesion affinity than silicon resin, the adhesiveness is improved despite the voice coil 30 being bonded to the joint 23 between the diaphragm main body 21 and the edge portion 22. .

  By attaching the diaphragm unit 20 in the mounting hole 15 of the case 10, the inside of the case 10 functions as a back cavity 70 unique to the speaker. The volume of the back cavity 70 is set to a value appropriate for the speaker. For this reason, a predetermined acoustic characteristic is ensured irrespective of the kind and structure of the device incorporating the speaker. In addition, since the back cavity 70 communicates with the outside of the case 10 through the long groove 12 and the vent hole 17, characteristic changes due to changes in atmospheric pressure and temperature are avoided, and damage to the diaphragm unit 20 occurs. The danger is eliminated, and in addition, the change in acoustic characteristics due to the back cavity 70 being omitted is avoided.

  The plurality of holding portions 16, 16... Holding the magnet unit 40 are adjacent so that the magnet unit 40 located in the back side of the diaphragm unit 20 and housed in the case 10 does not divide the back cavity 70. A space is formed between the holding portions. That is, the cavity on the front side and the cavity on the back side of the magnet unit 40 communicate with each other through a space formed between the adjacent holding portions 16 and 16.

  When the speaker is incorporated in the mobile phone, the spring terminals 50 and 50 are pressed against the substrate in the mobile phone and are electrically connected. It goes without saying that such a solderless connection is preferable from the viewpoint of the environment.

It is a perspective view which shows the external appearance of the speaker which concerns on one Embodiment of this invention from the front side. It is a perspective view which shows the external appearance of the speaker from the back side. It is a vertical side view of the speaker, and is a view taken along line XX in FIG. It is a perspective view which shows the rear frame which comprises the case of the speaker from an inner surface side. It is a perspective view which shows the front frame which comprises the case from the inner surface side. It is a longitudinal cross-sectional view which shows the spring terminal part in the speaker. It is a longitudinal cross-sectional view of the diaphragm unit used for the speaker. It is a longitudinal cross-sectional view which shows the manufacturing method of the diaphragm unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Case 10A Back frame 10B Front frame 11 Installation convex part 12 Long groove 13, 13 'Installation concave part 14 Terminal hole 15 Mounting hole 16 Holding part 17 Ventilation hole 20 Diaphragm unit 21 Diaphragm body part 22 Edge part 23 Joining Part 24 Holding part 25 Dome-shaped curved part 30 Voice coil 40 Magnet unit 50 Spring terminal 60 Baffle 70 Back cavity 80A, 80B Mold

Claims (7)

  The diaphragm body has a diaphragm unit in which an annular edge portion made of a different material softer than the body portion is joined and integrated on the outer peripheral portion of the diaphragm body portion, and the edge portion is curved in a convex direction toward the front side. A speaker having a dome shape and a dome-shaped curved portion formed in a tapered shape with a thickness gradually decreasing from an outer peripheral portion toward an inner peripheral portion.   2. The material constituting the edge portion is silicon, and the material constituting the diaphragm main body portion is polycarbonate, polyethylene terephthalate, polyetherimide, or polycarbonate / polybutylene terephthalate having good adhesion affinity with silicon. The speaker described.   The speaker according to claim 2, wherein the diaphragm main body portion overlaps the back side of the edge portion at a joint portion between the diaphragm main body portion and the edge portion.   The speaker according to claim 1, further comprising a case that encloses the diaphragm unit so that a back cavity is formed on a back side thereof.   The speaker according to claim 4, wherein the back cavity communicates with the outside of the case.   The speaker according to claim 5, wherein the back cavity communicates with the outside of the case through a long groove formed in the case.   The speaker according to claim 1, further comprising a spring terminal pressed against the device side when the speaker is incorporated into the device.

Images