JP5042376B1 - Fully driven speaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a full drive speaker capable of generating a practical sound pressure level while preventing deterioration of sound quality and having a large degree of freedom in designing a front shape.
SOLUTION: A full-surface driving type speaker includes first and second magnetic circuits in which magnetic circuits MC1 and MC2 having cylindrical magnetic gaps are arranged at equal intervals in the vertical and horizontal directions, and the magnetic gaps are arranged close to and opposed to each other. And a diaphragm 21 disposed on a neutral plane between these magnetic circuit groups and provided with a voice coil VC. The magnetic circuits MC1 and MC2 of the first and second magnetic circuit groups are opposed to each other with a ½ pitch shift in the vertical and horizontal directions. The voice coil VC does not cross the arcs of the outer periphery of the fan-shaped region corresponding to 90 degrees or 180 degrees of adjacent magnetic gaps arranged in close proximity to each other in the first and second magnetic circuit groups. It is formed along a line that is continuously connected with a single stroke.
[Selection] Figure 1

Description

  The present invention relates to a whole surface drive type speaker that is thin and miniaturized so as to be incorporated in a thin and small device.

  In recent years, for example, with the reduction in thickness and size of electric / electronic devices such as small flat-screen televisions, speakers built into these devices are required to be thinner. Moreover, sound reproduction at a practical sound pressure level is possible, and the front face shape of the speaker is required to have a high degree of design freedom so as to be compatible with various shapes depending on the mounting location.

  In general, a planar type is suitable for reducing the thickness of a speaker, and a full drive speaker is considered suitable if acoustic characteristics are emphasized in the planar type. However, although various types and configurations of flat-type and full-drive type speakers can be seen, those that sufficiently satisfy the above requirements have not yet been developed.

  Therefore, in the patent document 1, the present applicant arranges two or more magnetic circuits having a cylindrical magnetic gap on a plane, and connects the upper surfaces of the magnetic gaps with a line that does not intersect with one stroke. We proposed a “full-surface driving speaker” that uses a voice coil with a pattern that comes to the magnetic circuit.

  With this configuration, a speaker can be formed with a total height of one small magnetic circuit, and the effective linear density of the voice coil can be increased efficiently within a limited frontal area due to the shape of the connection of multiple magnetic circuits and wire rings. A thin speaker was realized.

JP 2010-245601 A

  By the way, in the “full-surface driving speaker” of the above-mentioned Patent Document 1, in order to realize a thin speaker unit of 3 mm or less, the magnetic circuit group is opposed to the voice coil only on one side of the diaphragm. For this reason, the magnetic flux loop to be used is a leakage loop that connects between the outer periphery of the short columnar magnet for forming the cylindrical magnetic gap and the inner periphery of the concave portion of the yoke.

  For this reason, the magnetic flux density varies depending on the location, and since there are few spatially uniform magnetic flux density portions, there is a possibility that distortion may occur during vibration with a large amplitude. Accordingly, although it is effective as a case where priority is given to thinness or a high-frequency loudspeaker having a relatively small amplitude, improvement in sound quality is desired in a low sound range having a large amplitude.

  The present invention has been proposed in view of the above, and an object of the present invention is to provide a full drive speaker capable of generating a practical sound pressure level while preventing deterioration in sound quality and having a large degree of freedom in designing the front shape. Is to provide.

  In order to solve the above-mentioned problem, the full drive speaker of the present invention according to claim 1 includes magnetic circuits MC1 and MC2 having cylindrical magnetic gaps MG1 and MG2 arranged vertically and horizontally at equal intervals, respectively. MG1 and MG2 are arranged on the neutral surface of the first and second magnetic circuit groups 11 and 12 arranged in close proximity to each other and in the space where the first and second magnetic circuit groups 11 and 12 are opposed to each other. A diaphragm 21 and a voice coil VC provided on the diaphragm 21 are provided. The first and second magnetic circuit groups 11 and 12 are configured so that each of the magnetic circuits MC1 and MC2 is ½ pitch vertically and horizontally. The voice coil VC corresponds to 90 degrees or 180 degrees adjacent to the adjacent magnetic gaps MG1 and MG2 disposed in close proximity to each other in the first and second magnetic circuit groups 11 and 12. You The arc of the outer periphery of the fan-shaped area, characterized by continuously be formed along the line connecting in a single stroke without crossover.

  According to a second aspect of the present invention, in the full drive speaker according to the first aspect, when the radius to the central portions AX1 and AX2 of the magnetic gaps MG1 and MG2 is R, the vertical and horizontal distances ΔL between the magnetic circuits MC1 and MC2 Are characterized by 2.4R to 3.2R, respectively.

  According to a third aspect of the present invention, in the full drive speaker according to the second aspect, the sector region corresponding to 180 degrees of the magnetic gaps MG1 and MG2 is a corner portion of the voice coil VC. .

  According to a fourth aspect of the present invention, in the full drive speaker according to the first aspect, the polarity of the magnetic circuit MC <b> 1 on the lower surface of the first magnetic circuit group 11 and the upper surface of the second magnetic circuit group 12. The magnetic circuit MC2 has a different polarity.

  According to a fifth aspect of the present invention, in the full-surface driving type speaker according to the first aspect, the magnetism at a position where the second and first magnetic circuit groups 12 and 11 face each other adjacent to the magnetic circuits MC1 and MC2. It is provided corresponding to the circuits MC2 and MC1, and further comprises openings 20 and 16 for radiating sound pressure generated by the vibration of the diaphragm 21 to the space opposite to each of the magnetic circuits MC1 and MC2. To do.

  According to the first to fifth aspects of the present invention, since the magnetic flux loop is not the leakage loop of the magnetic circuit but the main loop, a uniform magnetic flux space can be formed widely. In addition, the magnetic flux density can be increased by arranging the two magnetic circuit groups facing each other. As a result, a speaker with higher sensitivity can be realized in a wide amplitude region.

  Further, each part of the voice coil is continuously under the first magnetic circuit group or directly above the second magnetic circuit group except for the end portion, and crosses the magnetic flux almost over the entire length. As a result, a large number of radial magnetic flux loops are formed on the neutral surfaces of the two magnetic circuit groups. Further, the circumferential portion of the magnetic gap in the voice coil is perpendicular to the magnetic flux radially formed in the magnetic gap, and when the current is energized, the voice coil efficiently generates a driving force in the direction perpendicular to the neutral plane.

  In addition, since each magnetic circuit is shifted by ½ pitch in the vertical and horizontal directions, a large opening of about 0.8 × DM can be provided if the diameter of the magnet is DM, which is highly effective in improving sound quality. .

  Accordingly, it is possible to provide a full drive speaker that can generate a practical sound pressure level while preventing deterioration of sound quality and has a high degree of freedom in designing the front shape.

BRIEF DESCRIPTION OF THE DRAWINGS It is for demonstrating the basic structure of the full drive type speaker based on the Example of this invention, (a) A figure is a top view of two magnetic circuit groups and a voice coil, (b) A is A of FIG. FIG. FIG. 2 shows a first magnetic circuit group side in FIG. 1, (a) is a plan view, and (b) is a cross-sectional view taken along line A-A ′ of FIG. 1 (a). FIGS. 2A and 2B show the second magnetic circuit group side in FIG. 1, in which FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view taken along line A-A ′ in FIG. The diaphragm and voice coil in FIG. 1 are extracted and shown, in which (a) is a plan view, and (b) is a cross-sectional view taken along line A-A 'in FIG. It is sectional drawing which expands and shows a part of FIG.1 (b). It is for explaining the consideration when setting the interval of each magnetic circuit. (A) In the case of “ΔL = 2√2 · R”, (b) In the figure, “ΔL <2√2 · R” It is a figure which shows the case of. It is for explaining the consideration when setting the interval of each magnetic circuit. (A) The figure shows the case where the thickness of the yoke is considered, (b) The figure shows the case of “ΔL> 2√2 · R”. FIG.

  In the prior application (Japanese Patent Application No. 2010-120271), the present applicant has improved the sound quality and sensitivity by arranging the first and second magnetic circuit groups arranged symmetrically with the magnetic gap surfaces facing each other. In addition, a “thin full-surface drive speaker” was proposed.

  The present invention is a further improvement by combining the technique described in Patent Document 1 described above and the technique described in the prior application. That is, by performing the following (A) to (C), the sound quality is improved in a low sound range having a large amplitude.

  (A) In Patent Document 1, the magnetic flux loop used is a leakage loop, but by making it a main loop as in the previous application, the magnetic flux density is increased and the region that can be regarded as uniform is widened.

  (B) In the configuration of the repulsive magnetic circuit in which the same poles of the magnets are opposed to each other as in the previous application, if the arrangement density of the magnetic circuit is increased in order to increase the crossing of the coil current and the magnetic flux, the magnetism is generated on both sides of the diaphragm. The area covered by the circuit increases and the direct radiation area of the sound decreases. Therefore, the two magnetic circuit groups are arranged opposite to each other while being shifted by 1/2 pitch in the vertical and horizontal directions, and the polarities of the opposing magnetic circuits in the two magnetic circuit groups are changed.

  (C) In the configuration of the prior application, sound is emitted through an opening provided between adjacent magnetic circuits or a hole provided in the center of the magnetic circuit. Minimizing the formation of a structural acoustic circuit around the diaphragm is necessary to prevent deterioration in sound quality. In this case, it is important to increase the diameter of the opening and the hole as much as possible. In the configuration of the prior application, since an opening (hole) is provided in the gap between adjacent magnetic circuits, the diameter of the opening is limited to about 0.3 × DM when the diameter of the magnet is DM. However, a larger opening (through hole) of about 0.8 × DM can be provided by disposing the two magnetic circuit groups so as to be opposed to each other with a ½ pitch shift vertically and horizontally as described above.

  Based on the considerations as described above in (A) to (C), in the embodiment of the present invention, the full drive type speaker is configured as follows (1) to (4).

  (1) Two magnetic circuit groups in which cylindrical magnetic gaps are arranged at equal intervals in the vertical and horizontal directions are formed, and the surfaces of the magnetic gaps of these two magnetic circuit groups are arranged close to each other.

  (2) Each of the above two magnetic circuit groups is equally spaced so that the vertical and horizontal intervals (ΔL) are 2.4R to 3.2R, respectively, where R is the radius to the center of the magnetic gap. Line up with. These two magnetic circuit groups are arranged opposite to each other while being shifted by 1/2 pitch in the vertical and horizontal directions. Here, the polarities of the opposing magnetic circuits in the two magnetic circuit groups are different.

  (3) A voice coil is disposed on the neutral surface of the space between the two magnetic circuit groups. This voice coil is written in a continuous stroke without crossing the arcs on the outer circumference of the sector area corresponding to 90 or 180 degrees of adjacent magnetic gaps in the two magnetic circuit groups that are adjacent to each other. It is formed along the line connected by.

  (4) An opening (through hole) is provided on the opposing surface of each magnetic circuit in the two magnetic circuit groups.

  According to the above configuration, a large number of radial magnetic flux loops are formed on the neutral surfaces of the two magnetic circuit groups. This magnetic flux loop is not the leakage loop of the magnetic circuit but the main loop. Further, the voice coil in the circumferential direction of the magnetic gap is orthogonal to the magnetic flux formed radially in the magnetic gap, and when energized, the voice coil efficiently generates a driving force in the direction perpendicular to the neutral plane. Furthermore, the sound pressure generated by the vibration of the diaphragm can be effectively radiated from the opening to the space on the opposite side of the magnetic circuit.

  As a result, a practical sound pressure level can be generated while preventing deterioration of sound quality, and the degree of freedom in designing the front surface shape can be increased.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  1A and 1B are diagrams for explaining the basic structure of a full drive speaker according to an embodiment of the present invention. FIG. 1A is a plan view of two magnetic circuit groups and a voice coil, and FIG. It is an AA 'line arrow sectional view of a figure. 2 to 4 show the first and second magnetic circuit groups, the diaphragm and the voice coil in FIG. 1, respectively. FIG. 2A is a plan view, and FIG. a) It is an AA 'line arrow directional cross-sectional view of a figure.

  As shown in FIGS. 2A and 2B, in the first magnetic circuit group 11, a magnetic circuit of m rows and n columns, in this example, a circular magnetic circuit MC1 of 4 rows and 4 columns is arranged vertically and horizontally. ing. These magnetic circuits MC1 are equally spaced (ΔL pitch) so that the magnetic circuit MC1 becomes a square of 2.4R to 3.2R vertically and horizontally, where R is a radius to the central portion AX1 of the cylindrical magnetic gap MG1. It is arranged side by side.

  In each magnetic circuit MC1 of the first magnetic circuit group 11, a bottomed cylindrical yoke 14 is fitted into a recess 13a provided at the bottom of the housing 13, and the inner diameter of the yoke 14 is fitted in the yoke 14. A smaller cylindrical magnet 15 is accommodated and formed. Thereby, a cylindrical magnetic gap MG1 is formed between the inner surface of the yoke 14 and the outer periphery of the magnet 15. Further, in the housing 13 between the magnetic circuits MC1, openings (through holes) 16 are formed at positions corresponding to the magnetic circuits MC2 of the second magnetic circuit group 12.

  As shown in FIGS. 3A and 3B, the second magnetic circuit group 12 has the same configuration as the first magnetic circuit group 11, and in this example, a circular magnetic circuit of 3 rows and 3 columns is used. MC2 are arranged at equal intervals vertically and horizontally. Similar to the first magnetic circuit group 11, these magnetic circuits MC2 have a magnetic circuit MC2 of 2.4R to 3.2R vertically and horizontally, where R is the radius to the central portion AX2 of the cylindrical magnetic gap MG2. They are arranged at regular intervals (ΔL pitch) so as to form a square.

  In each magnetic circuit MC2 of the second magnetic circuit group 12, a bottomed cylindrical yoke 18 is fitted into a recess 17a provided at the bottom of the casing 17, and the inner diameter of the yoke 18 is fitted in the yoke 18. A smaller columnar magnet 19 is accommodated and formed. As a result, a cylindrical magnetic gap MG2 is formed between the inner surface of the yoke 18 and the outer periphery of the magnet 19. Furthermore, an opening (through hole) 20 is formed at a position of the housing 17 facing each magnetic circuit MC1 of the first magnetic circuit group 11.

  Then, as shown in FIGS. 1A and 1B, the first and second magnetic circuit groups 11 shown in FIGS. 2A and 2B and FIGS. 3A and 3B, 12, the surfaces of the magnetic gaps MG1 and MG2 are arranged close to each other and face each other. At this time, the magnetic circuits MC1 and MC2 are shifted vertically and horizontally by ½ pitch (ΔL / 2), in other words, by half a cycle. Thus, the central portion AX1 of the magnetic gap MG1 of the magnetic circuit MC1 and the central portion AX2 of the magnetic gap MG2 of the magnetic circuit MC2 are arranged to face each other.

  Here, the magnetic circuit MC1 has an S pole on the bottom surface and the magnetic circuit MC2 has an N pole on the top surface. The magnetic circuits MC1 and MC2 only need to have different polarities, and the lower surface of the magnetic circuit MC1 may be an N pole and the upper surface of the magnetic circuit MC2 may be an S pole.

  On the neutral surface between the magnetic circuits MC1 and MC2, a voice coil (flexible coil) VC is stretched between the side plates 13b and 13c at the end of the housing 13. As shown in FIGS. 4A and 4B, the voice coil VC is formed on a thin film that functions as the diaphragm 21 (or in the thin film). Then, arcs on the outer periphery of the fan-shaped region corresponding to 90 degrees adjacent to each other in the magnetic gaps MG1 and MG2 disposed in close proximity to each other in the first and second magnetic circuit groups 11 and 12 (180 degrees at the corner). Are formed in a pattern along a line that is continuously connected with a single stroke without crossover.

  Accordingly, as shown in an enlarged view of the region SE surrounded by the broken line in FIG. 1B in FIG. 5, the magnetic circuit MC1 and MC2 in the same forward direction (not the repulsive direction) are horizontally placed on the neutral plane. A radial flux loop is formed. Further, since this magnetic flux loop is also a main loop in which the N pole and the S pole face each other, the magnetic flux density is large and the area that can be regarded as uniform is wide.

  In addition, each of the circular portions of the voice coil VC held by the diaphragm 21 disposed in the neutral plane is disposed in the radial main magnetic flux loop, and when the voice coil VC is energized, the coil is neutral. A driving force in a direction perpendicular to the surface and the diaphragm 21 is efficiently generated.

  The central axes AX3 and AX4 of the openings 16 and 20 formed in the casings 13 and 17 are arranged to coincide with the central axes AX5 and AX6 of the magnets 15 and 19 of the magnetic circuits MC1 and MC2 that are opposed to each other. The As described above, since the magnetic circuits MC1 and MC2 are alternately arranged up and down, the openings 16 and 20 can be efficiently arranged using the gaps between the magnetic circuit paths MC1 and MC2. If the diameter of 19 is DM, a large opening of about 0.8 × DM can be provided.

  Therefore, the diaphragm 21 vibrates with the driving force when the voice coil VC is energized, and the sound pressure generated by the vibration is effectively applied to the space outside the casings 13 and 17 through the openings 16 and 20. Radiated and effective in improving sound quality.

  The interval ΔL between the magnetic circuits MC1 and MC2 is set based on the following consideration. The gap between the magnetic circuit MC1 when the circle in the gap of the magnetic circuit MC1 (circle in the center of the gap) and the circle in the gap of the magnetic circuit MC2 are in contact at four points (X1 to X4) as shown in FIG. ΔL is “√2 × 2R”. Therefore, ΔL = 2√2 · R (about 2.83R) ”.

  Further, when “ΔL <2√2 · R”, as shown in FIG. 6B, the intersections Y of the middle circles of the upper and lower magnetic circuits MC1 and MC2 are eight (Y1 to Y8), and the circumferential direction The uniformity of the magnetic flux density B is increased, which is advantageous in terms of driving force (Bil). Here, the driving force (Bil) is an electromagnetic force F (F = Bil, B: magnetic flux density, i: current, l: effective length of the coil) generated by Fleming's law by passing a current through the driving coil. is there.

  However, since the yoke 14 is thick, the minimum value that can actually be taken is about 2.4R. For example, as shown in FIG. 7A, when the outer diameter φ1 of the yoke 14 is 14 mm, the inner diameter φ2 is 12 mm, and the diameter φ3 of the magnet 15 is 10 mm, the distance ΔL between the magnetic circuit MC1 is “ΔL = 14 mm = about 2.55 R ”.

  On the other hand, when “ΔL> 2√2 · R”, the magnetic flux density B decreases. That is, as shown in FIG. 7B, the interference of the magnetic field between the magnetic circuits MC1 and MC2 is reduced and approaches the leakage magnetic field of a single magnetic circuit. When ΔL exceeds about 3.2R, the leakage magnetic field becomes dominant. Therefore, the preferable interval ΔL between the magnetic circuits MC1 and MC2 is in the range of 2.4R to 3.2R.

  According to the above configuration, since the magnetic flux loop to be used is the main magnetic flux loop as described above, it is possible to widely form a uniform magnetic flux space. Also, the magnetic flux density can be increased by the opposing arrangement of the magnetic circuit groups. Moreover, as shown in FIG. 1A, each part of the voice coil is continuously directly above or below the magnetic gap except for the end portion, and crosses the magnetic flux almost over the entire length. As a result, a uniform magnetic flux density space can be widened, and the magnetic flux density is high due to the configuration of the opposing magnetic circuit. Accordingly, it is possible to realize a loudspeaker with a wider amplitude region and higher sensitivity.

  Further, unlike the magnetic circuit group configured in the repulsive direction as in Patent Document 1, it is possible to magnetize after assembling the speaker, and the assembly (manufacturing process) can be simplified.

  Therefore, while preventing deterioration of sound quality, it is possible to generate a practical sound pressure level while being as thin as several millimeters, and has a large degree of freedom in designing the front shape, in other words, the shape design according to the installation location An easy full-drive speaker can be provided.

  In addition, although the thickness of the speaker is about twice that of the configuration of Patent Document 1 by arranging the two groups of magnetic circuits to face each other, it can still be 10 mm or less in the case of a small magnetic circuit. Compared with, it is still at a sufficiently thin level.

  Further, in the above-described embodiment, an example is described in which the first magnetic circuit group 11 is a magnetic circuit MC1 with 4 rows and 4 columns, and the second magnetic circuit group 12 is a magnetic circuit MC2 with 3 rows and 3 columns, each arranged in a square. did. However, the first magnetic circuit group 11 is formed by the magnetic circuit MC1 of m rows and n columns (where m and n are integers of 2 or more), and the second magnetic circuit group 12 is formed of (m−1) rows (n -1) Needless to say, the magnetic circuit MC2 may be arranged in a row, and may be arranged in various shapes other than a square.

  Although the present invention has been described using the embodiments and examples, the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the scope of the invention at the stage of implementation. Is possible. The above-described embodiments and examples include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed structural requirements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiments and examples, at least one of the problems described in the column of problems to be solved by the invention can be solved, and the column of the effect of the invention In the case where at least one of the effects described in (1) is obtained, a configuration in which this configuration requirement is deleted can be extracted as an invention.

11 First magnetic circuit group 12 Second magnetic circuit group 13, 17 Housing 13a, 17a Recess 13b, 13c Side plate 14, 18 Yoke 15, 19 Magnet 16, 20 Opening 21 Diaphragm MG1, MG2 Magnetic gap MC1, MC2 Magnetic circuit ΔL interval VC Voice coil AX1, AX2 Center part AX3-AX6 Center axis

Claims (5)

The first and second magnetic circuits (MC1, MC2) having cylindrical magnetic gaps (MG1, MG2) are arranged at equal intervals in the vertical and horizontal directions, and the magnetic gaps (MG1, MG2) are arranged in close proximity to each other. Magnetic circuit group (11, 12) of
A diaphragm (21) disposed on the neutral surface of the space facing the first and second magnetic circuit groups (11, 12);
A voice coil (VC) provided on the diaphragm (21),
In the first and second magnetic circuit groups (11, 12), the magnetic circuits (MC1, MC2) are opposed to each other with a ½ pitch shifted vertically and horizontally,
The voice coil (VC) corresponds to the adjacent 90 degree or 180 degree of the magnetic gap (MG1, MG2) arranged in close proximity to each other in the first and second magnetic circuit groups (11, 12). A full-surface drive type speaker characterized by being formed along a line that continuously connects arcs on the outer periphery of the fan-shaped region with a single stroke without crossing.   When the radius to the central part (AX1, AX2) of the magnetic gap (MG1, MG2) is R, the vertical and horizontal intervals (ΔL) of the magnetic circuits (MC1, MC2) are 2.4R to 3.2R, respectively. The full drive speaker according to claim 1, wherein:   3. The full drive speaker according to claim 2, wherein the fan-shaped region corresponding to 180 degrees of the magnetic gap (MG1, MG2) is a corner portion of the voice coil (VC).   The polarity of the magnetic circuit (MC1) on the lower surface of the first magnetic circuit group (11) is different from the polarity of the magnetic circuit (MC2) on the upper surface of the second magnetic circuit group (12). The full drive speaker according to claim 1.   Adjacent to each of the magnetic circuits (MC1, MC2) and corresponding to the magnetic circuit (MC2, MC1) at a position facing the second and first magnetic circuit groups (12, 11), the vibration 2. The entire surface according to claim 1, further comprising openings (20, 16) for radiating sound pressure generated by vibration of the plate (21) into a space opposite to each of the magnetic circuits (MC 1, MC 2). Drive type speaker.

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