JPS60223400A - Flat type speaker - Google Patents

Abstract

PURPOSE:To provide a smooth sound pressure versus frequency characteristic by driving a square position being nearly the center of an circumscribed quadrangle and an inscribed quadrangle of a nodal circle formed at the resonance point of the vibration mode when a flat diaphragm is vibrated freely so as to suppress the peak of a frequency characteristic at the 1st order resonance point. CONSTITUTION:A lower end connecting part of a driving body 3 with a voice coil 2 is formed circular and an upper connecting part with the flat diaphragm 4 is a conical square trapezoid connected to the central position between the circumscribed quadrangle and the inscribed quadrangle of a nodal circle formed at the resonance point of the vibrating mode (0, 1) of the flat diaphragm 4. That is, the upper end of the driving body 3 is coincident with a square S positioned at the midpoint between the circumscribed quadrangle Q and the inscribed quadrangle R of the nodal circle P having a diameter of 0.68A at the resonance point of the vibrating mode (0, 1) at the free vibration of the flat diaphragm 4 of a square whose side is A.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a flat speaker having a flat diaphragm, and particularly aims to provide a flat speaker with improved characteristics.

(b) Prior Art In recent years, a flat plate type nupika that uses a flat diaphragm to drive the inside of the flat diaphragm has been put into practical use.The structure thereof is shown in, for example, Japanese Patent Publication No. 57-40719.

That is, as shown in FIG. 1, this flat-plate speaker includes a magnetic circuit (1) of an external magnetic type, a voice coil (2) disposed within a magnetic gear G of the magnetic circuit (1), and a voice coil (2) disposed within a magnetic gear G of the magnetic circuit (1).
L/[21] A truncated cone-shaped driver (3), a flat diaphragm (4) fixed to the driver (3), and a frame (5) around the periphery of the flat diaphragm (4). ), and a tamper (7) that straddles the driver (3) and the frame. facing,
The inside of the flat diaphragm (4) is driven by a truncated cone-shaped driver (3), and the frequency characteristics of a flat speaker that drives the inside of the flat diaphragm (4) are as follows. , as shown by the broken line a in FIG. 3 and the broken line a in FIG.
A sharp peak occurs at the primary resonance point around 2KHz, so if this is used as a low-range speaker and is connected to a mid-range and high-range loudspeaker to configure a multiway system, this sharp peak will have an adverse effect. The crossover frequency must be set low. Alternatively, it has had drawbacks such as requiring the use of a high-cut filter that exhibits a sharp fall characteristic.

(C) Purpose of Departure J The Departure J was created in consideration of the above points, and is a flat-plate speaker that suppresses the peak of frequency characteristics at the primary resonance point and exhibits smooth sound pressure frequency characteristics. We aim to provide the following.

B) Structure of the Invention The flat plate type speaker of the present invention has a rectangular position approximately at the center of the circumscribed and inscribed rectangles of the nodal circle, which is the resonance point of the vibration mode (0, 1) when the flat plate diaphragm is allowed to freely vibrate. It is something that is driven.

Embodiment FIGS. 2(a) and 2(b) show a partially cutaway plan view and a sectional view of an embodiment of a flat speaker according to the present invention.

In these figures, (1)' to (7)' indicate a magnetic circuit to a damper corresponding to each component f1j to (7) in Fig. 1, and an external magnetic type magnetic circuit ( A cylindrical voice coil /I/(21') is arranged in the annular magnetic gap G of 1)', and the voice coil 1v (2) is a damper (7) attached to the frame (5)' connected to the magnetic circuit fil.
)' is held flexibly by the frame (5t) and the edge (6
The square diaphragm uf attached via 1 and the voice coil (2f) are connected by a truncated cone-shaped driver (3f).

The difference between the speaker according to the embodiment of the present invention and the conventional speaker shown in FIG. 1 is in the driver (3)'.
The lower end connecting part with the voice coil (2f) is circular, and the upper end joining part with the flat plate diaphragm (d) is the circumference of a 1'' circle created at the resonance point of the vibration mode (0, 1) of this flat plate diaphragm +41. It has a truncated cone shape with a square connected to the center of the quadrilateral and the inscribed quadrilateral.

That is, the upper end of this driver (3) is as shown in FIG.
- Square flat plate diaphragm with side A + v1 of diameter 0.68A at resonance point of vibration mode (0,1) during free vibration of d
] This matches the square S located between the circumscribed quadrangle Q and the inscribed quadrangle R of the circle P.

The frequency characteristics of the flat speaker of the present invention having such a square diaphragm of 12 cm on a side are as shown by the solid line in FIG. 4, and in FIG. It can be seen that the peak and depth at the first resonance point around 2 KHz are suppressed compared to C).

Although the explanation has been given above regarding a flat speaker having a square diaphragm, the procedure E)q can also be applied to a flat speaker having a circular diaphragm as shown in FIG.

That is, in this case, the upper end of the driver f3r is connected to a circular flat plate diaphragm (4[vibration mode during free vibration (0°1)
It is best to have a shape that matches the square S at the midpoint between the circumscribed quadrangle Q and the inscribed quadrangle R of the nodal circle P with a diameter of 0.68 A at the resonance point.

The frequency characteristics of the speaker of the present invention having a new circular diaphragm with a diameter of 12 - are shown by the solid line 6 in FIG. 3, and the nodal circle P
Compared to the frequency characteristics (broken line a) of a conventional speaker for driving, peaks and dips around 2 KHz are suppressed.

(F) Effects of the Invention As can be clearly seen from the above explanation, the flat plate type speaker of the present invention has two shapes: Since it drives a substantially central square position, the peak near the first resonance point in the frequency characteristics is higher than that of a drive that directly drives the nodal position.

Dip can be suppressed and this characteristic can be greatly improved.

Therefore, it becomes possible to reproduce a wide band using a flat speaker, and a wide range of applications to various multiway systems can be expected.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional flat speaker, Figure 2 (a)
, (b)Vi A partially cutaway plan view and a vertical sectional view of an embodiment of the flat speaker of the present invention, FIGS. 3 and 4 are frequency characteristic diagrams, and FIGS. 5 and 6 show different shapes, respectively. FIG. 3 is a schematic diagram of driving locations on the diaphragm of FIG. o) (1)'...Magnetic circuit, (2) (P)...Voice coil, +31is/...m8 body, 1n (d=4 plate swing a plate, f5] (5f ・= 7 re -mu, (6) (
6f... Edge, (7) (7f... Damper. Applicant: Sanyo Electric Board Co., Ltd. Agent Ben Mj Shisano Shizuinu Figure 2 + L0L + Figure 3 1D 31Lj Branch

Claims (1)

[Claims] a magnetic circuit, a voice coil μ disposed in a magnetic gap of the magnetic circuit, a driving body connected to the voice coil μ having one end circular and the other end square, and a flat plate supported by the other end of the driving body. It consists of a diaphragm and an edge for connecting the periphery of the diaphragm to the frame, and is composed of a circumscribed quadrilateral and an inner circle of a nodal circle that is the resonance point of the vibration mode (0, 1) when the flat diaphragm is caused to vibrate. A flat speaker characterized by driving a substantially central position of a tangent rectangle.