JPH01223898A - Acoustic diaphragm member and its manufacture - Google Patents

Abstract

PURPOSE:To maintain surface glitter carrying various pictures and to improve the degree of freedom for application of coloring by adhering a thermoplastic resin film having a horogram pattern face to a plate base made of a thermoplastic resin. CONSTITUTION:A laminator is formed by a plate 4 made of a thermoplastic resin and a thermoplastic resin film 1 adhered to the plate base 4 and having a horogram pattern face. In order to obtain the horogram pattern face, the film 1 and an object body 2 are arranged to a prescribed position and an optical system 6 such as a half mirror 5 splits a laser beam 4 from a laser light source 3 into an object light 7 radiated onto the object and a reference light 8 radiated onto the film at a prescribed angle. When the object light is radiated onto the object, the object light is reflected and refracted by the object and interfered with the reference light 8 and the interference fringe of the wave front is recorded on the film face as rugged or contrast horogram pattern face and then copied. Thus, the diaphragm member with satisfied design is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an acoustic diaphragm used in speakers and the like.

BACKGROUND ART In general, a diaphragm used as an acoustic diaphragm is required to be lightweight, rigid, have an appropriate internal loss, and have a ratio of Young's modulus E to density ρ as large as fr77. Paper, synthetic resin, metal, etc. have been used as materials for conventional diaphragms.

A diaphragm made of paper material has a large internal loss and can provide flat sound pressure frequency characteristics, but on the other hand, it has low rigidity, which causes split vibrations from the low frequency band and deteriorates transient characteristics and distortion characteristics. Furthermore, a diaphragm made of paper material easily absorbs moisture, which causes changes in sound quality, and also tends to cause deterioration of sound quality over time.

Metal diaphragms have high rigidity but low internal loss, making it difficult to damp high-frequency resonances, so they are used for medium and high-frequency diaphragms that can drive high-frequency resonances out of the audible frequency range. Even if it is possible, it is not suitable for use as a bass diaphragm.

In diaphragms made of synthetic resin materials such as polymeric thermoplastic side resins, instability of physical properties during production is not much of a problem because they have no hygroscopicity and have large internal losses. In addition, synthetic resin materials had the disadvantage of low rigidity, but recently they have been made to have higher rigidity by adding powdered fillers such as carbon fiber, carbon graphite, mica, and whiskers. Things are also being developed.

However, when diaphragms containing fillers in these synthetic resins are molded using a molding method such as injection molding, vacuum molding, or pressure molding, the surface gloss of the diaphragm may decrease, or the color tone or color may be reduced. There was a problem that some people couldn't get what they wanted. In addition, in order to obtain diaphragms with rich patterns, tones, and colors, diaphragms that are coated with paint or laminated with films have been developed, but these have not been satisfactory due to design constraints.

SUMMARY OF THE INVENTION An object of the present invention is to provide an acoustic vibrating member that supports various images, maintains surface gloss, and has a high degree of freedom in applying colors, etc., and a method for manufacturing the same.

The acoustic vibration member of the present invention is characterized in that it is composed of a laminate consisting of a plate-like base made of a thermoplastic resin and a thermoplastic resin film adhered to the plate-like base and having a hologram pattern surface. do.

The method for manufacturing an acoustic vibration member of the present invention is to produce a continuous sheet of a thermoplastic resin or a composition in which fine scale-shaped, fiber-shaped, or hollow body-shaped solid particles or a mixture thereof are dispersed in the thermoplastic resin. a continuous thermoplastic resin film, a hologram pattern surface is formed on at least one main surface of the continuous thermoplastic resin film, and the plate-shaped base and the thermoplastic resin film are adhered while being pressed together. It is characterized by being made into a laminate and heat-molded.

Example Embodiments of the present invention will be described below with reference to the drawings.

(1) Plate-shaped substrate Prepare pellet-shaped polypropylene as the thermoplastic resin that composes the plate-shaped substrate, add additives as necessary,
Both are processed using a mixing and kneading machine and made into continuous sheets using a calender machine, etc. When the plate-like substrate is made into a mixture with solid particles in the form of scales, fibers, or hollow bodies, mica powder, carbon graphite powder, hollow glass beads, and carbon fiber powder are mixed as fillers. Other thermoplastic resins that can be used include PVC, PET, and PE.

The resulting composition has a sheet forming temperature (approximately 230 to 260°C
), it is possible to form a sheet, and further, by passing it through several stages of rolling cooling rolls, a continuous sheet plate-like substrate of any thickness can be obtained.

(2) Thermoplastic resin film with hologram pattern surface Holography is a technology for recording and reproducing images of objects using holograms, and resin films with rich tones and colored surfaces have been developed using holograms. There is. A hologram is a recording of interference fringes created by adding a coherent reference beam to diffracted light from an object to cause interference. There are two types of holograms: transmission type and reflection type.

Holography is outlined below. When recording a hologram, as shown in FIG. 1, a film 1 coated with photoresist in advance and a subject 2, that is, an object to be recorded, are prepared.

A film 1 and a subject 2 are placed in a predetermined position, and a laser light 4 from a laser light source 3 is irradiated onto the object via an optical system 6 such as a half mirror 5, and an object light 7 is irradiated onto the film at a predetermined angle. Divide 8. The lens 9 in the optical system has a short focal length in order to spread the laser beam.

When the object light is illuminated on the object, the object light 7 is reflected and diffracted by the object and interferes with one of the reference beams 8, and the interference fringes of their wavefronts are recorded on the film surface as an uneven or light and shaded hologram pattern surface. Ru.

When reproducing a hologram, as shown in FIG. 2, when white light 10 is irradiated from the direction of incidence of the reference light during recording, the reproduction light 11 is reflected by the Bragg beam from the hologram pattern surface of the film 1, creating a virtual image 12 or tertiary image of the subject. A monochromatic image of the original real image is reproduced (Lippmann method).

Furthermore, the hologram pattern surface can be duplicated, and in the case of a hologram pattern surface of light and shade (amplitude hologram),
It can be obtained by contact printing, or, in the case of an uneven hologram pattern surface (phase hologram), by plating and peeling off the hologram pattern surface, creating a master of the reverse convex surface, and pressing transparent plastic.

In the manner described above, a duplicate film in which a polymeric resin film is subjected to hologram processing can be obtained by direct recording or duplication. A polypropylene film is used as the hologram-processed copy film. Other materials include thermoplastic PE and PVC.

PET etc. can be used.

There are other types of holograms that primarily function as diffraction gratings. This is a mass-produced hologram that creates an iridescent prism effect by applying fine embossing to the film and providing a reflective film. It may also be a laminated diaphragm using a mass-produced embossing hologram master.

In the case of this example, since the direct or duplicate hologram is a laminated diaphragm in the shape of a cone, dome, or flat plate, the reference beam of the laser beam is irradiated at various positions depending on the shape of the diaphragm during recording. can do. When such a diaphragm is incorporated into a speaker, the positions of the reference light source and the point light source of reproduction light are varied in consideration of the optimal listening position of the viewer. Normally, in the case of a white light source, it is better to irradiate from an angle range of about 10 degrees with respect to the normal direction of the hologram pattern surface to obtain a reproduced image.

(3) Formation of laminate A polypropylene film subjected to hologram processing and a continuous sheet plate-like substrate are laminated and attached.

In this case, if necessary, a corona discharge treatment is performed in advance to polarize the surface of the plate-like substrate. As shown in FIG. 3, a urethane adhesive 3 is applied to a thickness of several μm on the non-hologram-processed surface of a polypropylene film 1 that has undergone hologram processing, and a continuous sheet is applied to the film surface with the adhesive layer 3. A laminate is obtained by bonding the plate-shaped substrates 4 and bonding the resin film to the plate-shaped substrates while applying pressure between pressure rolls. A filler 2 made of finely shaped solid particles is dispersed in the thermoplastic resin of the plate-like substrate 4 .

In the above process, the thickness of the thermoplastic resin film is 2
0 to 300 μm, and the thickness of the laminate is 0.1 to 1.
0++++n. If it is outside this range, the mass will be too large and the characteristics as a vibrating member will not be obtained.

Next, the above-mentioned laminate is heated and softened, and then molded using a mold having an arbitrary shape, such as a cone shape, a dome shape, or a flat plate shape, using a vacuum, compressed air, or heating mold.

As an example, a hologram-processed film laminated diaphragm and center cap were created using the following material combinations, and a speaker was manufactured.

(Example 1) Plate-shaped substrate: Thickness of polypropylene alone: 0.40 (mm) Film: Polyester thickness: 60: (μm) (Example 2) Plate-shaped substrate: Mica 30 wt, % added polypropylene Thickness: 0. 40 (mm) Film: OPP film (polypropylene) thickness 60
: (μm) (Example 3) Plate-shaped substrate: 20 Wt carbon fiber, % added polypropylene Thickness: 0.40 (mm) Film: OPP film (polypropylene) Thickness 60
: (μm) Furthermore, in order to compare the conventional products and the examples, the following comparative examples 1 to 4 of vibrating members were created.

(Comparative Example 1) Mica 30wt, % added polypropylene thickness 0.4 [i
(mm) (Comparative Example 2) Carbon fiber 20wt, % added polypropylene Thickness: 0.
46 (Na) (Comparative Example 3) Polypropylene wt, 100wt, % Thickness: 0.46 (mm) (Comparative Example 4) Paper thickness by normal papermaking: 0.4tli (mm) Above Examples 1 to 3 and comparison The properties of Examples 1 to 4 are shown in Table 1.

Comparative Examples 1 and 2 in Table 1 have higher rigidity than Comparative Examples 3 and 4. It can be seen that in Examples 2 and 3, there is almost no deterioration in physical properties due to lamination of films.

Furthermore, looking at the molded diaphragm and center cap, in Examples 1 to 3, a reproduced image of the subject was obtained by performing hologram processing. Furthermore, it was found that the image of living things changes slightly when exposed to light and when the diaphragm and center cap vibrate. Furthermore, various images could be obtained by using arbitrary objects.

Next, using the diaphragm and center cap of Example 2, an electrodynamic cone-shaped speaker (woofer), which is an electroacoustic transducer, as shown in the cross-sectional view of FIG. 4 was manufactured. In this electrodynamic speaker, a pole piece 22 is placed on the center of the back plate 21, and a magnet 23 is placed on the periphery of the pole piece 22. Plate 24 is magnet 2
3 to form a magnetic gear with the pole piece 22. A voice coil 25 is provided in the magnetic gap.
A voice coil bobbin 26 wound with is inserted so as to be able to vibrate freely, and the voice coil bobbin 26 is supported by a damper 27. A cone-shaped diaphragm 28 is coupled to the voice coil bobbin 27 at its center, and a center cap 29 is attached to the end of the cone-shaped diaphragm 28 . The periphery of the opening of the diaphragm 28 is supported by a frame 31 via an edge 30.

The edge 30 is further secured to the frame 31 by a gasket 32. Note that the lead wire of the voice coil 25 is connected to a terminal 34 provided on the side surface of the frame 31 via a tinsel wire 33.

The speaker assembled using the diaphragm of Example 2 has a fifth
As shown in the figure, the sound pressure frequency characteristics were wide-band and flat with no peaks.

From the above, this embodiment is required for a diaphragm. This is an acoustic vibration member that does not deteriorate its physical properties and has an unprecedented appearance and design.

Effects of the Invention As described above, according to the present invention, by performing hologram processing, any three-dimensional image, laminated image, or planar image can be made to appear on a flat surface as it is, and by molding it into an acoustic diaphragm. Therefore, an acoustic vibrating member that is unprecedented in terms of appearance and design can be obtained.

[Brief explanation of the drawing]

Figures 1 and 2 are schematic diagrams for explaining how a hologram is recorded and reproduced on a diaphragm according to the present invention, Figure 3
4 is a cross-sectional view of a speaker using the diaphragm according to the invention, and FIG. 5 is a frequency characteristic diagram of the speaker using the diaphragm according to the invention. Explanation of symbols of main parts 1... OPP film 2... Filler 3... Urethane adhesive 4... Platy base 21... Pack plate 22... Pole piece 23... Magnet 24... Plate 25... Voice coil 26... Voice coil bobbin 27... ... Damper 28 ... Cone-shaped diaphragm 29 ... Center cap 30 ... Edge 31 ... Frame 32 ... Gasket 33 ... ... Kinshi Line Figure 1 and Figure 2 R Table

Claims (1)

[Scope of Claims] (1) A laminate consisting of a plate-shaped substrate made of a thermoplastic resin and a thermoplastic resin film adhered to the plate-shaped substrate and having a hologram pattern surface. Acoustic vibration member. (2) The acoustic vibration member according to claim 1, wherein fine scale-shaped, fiber-shaped, or hollow body-shaped solid particles, or a mixture thereof, are dispersed in the thermoplastic resin. (3) The thickness of the thermoplastic resin film is 20 to 300 mm.
μm, and the thickness of the laminate is 0.1 to 1.0 m
The acoustic vibration member according to claim 1 or 2, wherein the acoustic vibration member is m. (4) A thermoplastic resin or a composition in which fine scale-shaped, fiber-shaped, or hollow body-shaped solid particles or a mixture thereof are dispersed in the thermoplastic resin is formed into a continuous sheet-like plate-like substrate, and a continuous sheet is formed. A hologram pattern surface is formed on at least one main surface of the thermoplastic resin film, and the plate-like substrate and the thermoplastic resin film are bonded together while being pressed to form a laminate, which is then heat-molded. A method of manufacturing an acoustic vibration member. (5) The manufacturing method according to claim 4, wherein the thermoforming is performed under compressed air or vacuum.