SK26098A3 - A portable compact disc player - Google Patents

Abstract

A portable compact-disc player (41), characterised by an opposed pair of loudspeakers (81) attached to the player, and in that each loudspeaker comprises a distributed mode acoustic radiator having a transducer (9) wholly and exclusively mounted thereon to vibrate the radiator to cause it to resonate.

Description

Portable compact disc player

Technical field

The present invention relates to a portable compact disc player, and more particularly to a compact disc player comprising speakers comprising panel acoustic radiating elements.

BACKGROUND OF THE INVENTION

GB-A-2262861 discloses a panel loudspeaker comprising a resonant multi-mode radiator consisting of a uniform composite plate comprising a core having a transverse cellular structure surrounding the two skins, the plate having a bending strength ratio (b) in all directions to a cubic power of panel weight per unit area (μ) equal to at least 10, a fastener carrying or supporting said plate to the support body in a free, non-damped manner, and an electromechanical excitation means designed to drive multi-mode resonance in the radiating an electrical input board within the working frequency range of the speakers.

US-A-5,349,575 discloses a portable compact disc player comprising a thin body and a pair of speakers that are detachably suspended on the body.

SUMMARY OF THE INVENTION

Individual embodiments of the invention use elements having properties, e.g. the structure and configuration generally and / or specifically described in WO 97/09842 relating to this application. Thus, these elements have the ability not to dampen and propagate the input vibration energy by bending waves in the functional surface or functional surfaces that extend transversely to the thickness of the element, often but not necessarily at the edge of said element or elements. They are configured with or without anisotropy of flexural strength such that the resonant modes of flexural wave vibration distributed over the entire surface of the element favorably affect the acoustic connection with the ambient air, and have predetermined preferred positions or locations for the transducer means therefor. functionally active or moving parts effective depending on the acoustic vibration activity in said area and on signals, usually electrical, corresponding to the acoustic measure of such vibration activity. In co-pending international patent application WO 97/09842, which has the same priority, the above-mentioned elements for passive acoustic devices without converter means, such as e.g. reverberation or acoustic filtering equipment, or acoustic sounding of a room or room, as well as active acoustic equipment with transducers, including sound sources or loudspeakers with a remarkably wide frequency range, where input signals are applied to that sound, or microphones that are exposed to sound they transmit to other signals.

In particular, the invention relates to active acoustic devices, such as e.g. speakers for portable compact disc players. In the following description and claims, the term compact disc includes analogue digital encoded discs, such as e.g. digital video discs.

The above elements in these devices are referred to as distributed mode acoustic radiators and have the characteristics described in patent application WO 97/09842 or other characteristics described in this patent application.

SUMMARY OF THE INVENTION The present invention provides a portable compact disc player having a pair of opposed panel speakers each having an element that has the ability to dampen and propagate input vibration energy by bending waves in at least one functional area extending transversely to its thickness to have resonant bending vibration modes. over at least one surface and predetermined preferred positions within the surface for the transducer means, and a transducer mounted wholly and exclusively on the element in one of the vibration positions of the element to achieve resonance of the acoustic radiator element which provides acoustic output during its resonance. The portable CD player may include a body having a CD tray and a lid adapted to close the disc overlap, and the speakers may be attached to the lid. Alternatively, each of the speakers may be hidden in a slot of the lid for sliding between a non-functional position in which each of the speakers is substantially completely hidden in the slot and a functional position in which the speakers are arranged on opposite sides of the lid. Each radiator may be a rigid light panel having a cellular core surrounded by opposing shells. This radiator can be carried in the surrounding frame. A flexible hinge may be inserted between this frame and the radiator.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, exemplary embodiments of the invention are illustrated in the accompanying drawings, in which:

Fig. 1 shows a distributed mode loudspeaker as described in WO97 / 09842, FIG. 2a shows a partial section along the line A-A in FIG. 1, FIG. 2b shows an enlarged cross-section of a distributed mode radiator of the type shown in FIG. 2a, showing two alternative designs of this emitter, FIG. Fig. 3 shows a perspective view of a first embodiment of a portable CD player in a dysfunctional position; 4 is a perspective view of the player of FIG.

FIG. 5 shows a view of part of the player of FIG. 3 and 4, FIG. 6 is a perspective view of a second embodiment of a portable CD player, and FIG. 7 shows a view of part of the player of FIG. 6th

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, there is shown a panel loudspeaker 81 of the same type as described and claimed in co-pending application WO97 / 09842 with the same priority, the loudspeaker comprising a rectangular frame 1 carrying a flexible hinge 3 around an inner edge carrying a sound emitting panel 2 with distributed modes . Converter 9, e.g. the transducer described in detail in related patent applications WO / 09859, WO97 / 09861, WO97 / 09858 with the same priority is mounted wholly and exclusively to panel 2 or panel 2. at a predetermined position defined by x and y coordinates, these coordinates being calculated so that as described in co-pending application WO97 / 09842 with the same priority, to generate a bending waveform in the panel to cause resonance of the panel forming the radiator providing acoustic power during its resonance.

The transducer (9) is driven by a signal amplifier (10), e.g. a low-frequency amplifier coupled to this converter by means of conductors (28). The amplifier load and power requirements can be quite normal, i. as with conventional conical loudspeakers, with a sensitivity of the order of 86 to 88 dB / W under idle load conditions. The impedance load of the amplifier has a strong resistive character at 6 Ω and a load rating of 20 to 80 W. If the core of the panel and / or its sheath are made of metallic material, they serve as heat dissipation of the converter to dissipate heat from the converter's coil and improve performance.

In FIG. 2a and 2b show typical cross-sections of the loudspeaker 81 in FIG. 1. FIG. 2a, it is clear that the frame 1, the elastic hinge 3 and the panel 2 are connected to each other in the joints 20 by means of adhesive means. Said frame may be a lightweight frame, e.g. an image extruded frame of metallic material, e.g. aluminum alloy or plastic. Suitable materials for the flexible hinge may be flexible materials, e.g. foam rubber and foam plastic. Suitable adhesives for the joints 20 may be epoxy, acrylate and cyanoacrylate resins, or other adhesives.

It can be seen from Figure 2b that the panel 2 is formed by a rigid light panel having a core 22 made e.g. of rigid plastic foam 97, such as e.g. cross-linked polyvinyl chloride, or a core structure 98 with a cellular structure such as e.g. a honeycomb-shaped core made of metal foil, plastic or other similar material, the chambers of this structure extending transversely to the panel surface and closed by opposing sheath layers 21 made of a material such as e.g. paper, plastic or metal foil. If the casings are made of plastic, the casings can be reinforced in a known manner, e.g. carbon, glass, Kevlar fibers, and the like.

Thus, the envisaged sheathing materials and reinforcements include carbon, glass, Kevlar (RTM), Nomex (RTM), i.e., carbon, glass, and liner. aramid, fibers in different layers and bonds, as well as paper, laminated paper, melamine and various synthetic plastic films with high modules, such as e.g. Mylar (RTM), Kaptan (RTM), polycarbonate, phenolic, polyester or related plastics, fiber reinforced plastics and metal foils. Based on Vectra liquid crystal quality research based on polymeric thermoplastics, it has been found that polymeric thermoplastics can be used to form thin coatings of small size, e.g. with a diameter of about 30 cm by injection. This material itself forms an oriented crystalline structure in the injection direction, which is an advantageous direction for good propagation of high sound frequencies from the drive point towards the edge of the panel.

The additional shaping of said or other thermoplastics allows the molding tools to have locating and registration features, such as grooves or rings for accurately positioning a part of the transducer, e.g. excitation coil and / or magnet hinge. Furthermore, in the case of a weaker core material, it may be advantageous to locally increase the thickness of the sheath, e.g. in a surface or ring with a diameter of up to 150% of the diameter of the sensor, to enhance said surface and advantageously couple the vibration energy in the panel. In this way, the high-frequency response can be improved for some softer foam materials.

The envisaged core layer has a honeycomb structure or a corrugated structure formed of aluminum alloy foil, Kevlar (RTM), Nomex (RTM), unpainted paper or paperboard and sheets of various synthetic plastics, also cellular or foamed plastic or fiber materials, even aerogel metals if they have a suitably low density. Some suitable core layer materials have a self-sheathing capability in manufacture and / or have sufficient strength to be interposed between the sheath layers without the use of lamination. The core-material with a high-performance cellular structure is known under the trade name Rohacell, which material is suitable for a radiant panel without being wrapped in a sheath. From a practical point of view, in order to achieve overall lightness and strength suitable for specific purposes, this objective includes in particular the optimization of core contributions, sheath layers and transitions therebetween.

In several preferred embodiments of the panel, sheaths of metal and metal alloys, or alternatively carbon fiber reinforced materials, have been used. These panel designs as well as panel designs in which the Aero7 gel alloy has been used, or in which the core has a honeycomb structure of metallic material, have a high frequency shielding capability that is important for the compatibility of the electromagnetic energy emitting device. Conventional cone-type panels or loudspeakers do not have the capability of said shielding.

In addition, preferred forms and electrodynamic transducers have tic radiation or loudspeaker loudspeakers have large magnetic up to 1 m unless thyroid measures are performed.

of piezoelectric transducers negligible electromagnetic field. Conventional Field, Distance-Specific Compensation For When it is important to provide or maintain shielding in a given application, electrical connections can be made such that conductive parts of a suitable DML panel, electrically conductive foam, or similar interfaces can be used to mount edge areas.

The hinge 3 may damp the edges of the panel 2 to prevent excessive movement of the edges of the panel. In addition, additional buffering means, e.g. means in the form of patches associated with the panel at selected positions to damp the excessive movement of the panel to achieve a uniform resonance distribution across the panel surface. These patches are. they may be made of a bitumen-based material typically used in conventional loudspeaker enclosures or a flexible or rigid polymeric sheet material. Some materials, especially paper and board, and some types of core materials may be self-limiting. If desired, damping can be enhanced in the construction of the panels using adhesives that are flexible and not rigid when cured.

Said effective selective damping comprises specific panel applications comprising the sheet material of the composition permanently associated with the panel. The edges and corners may be particularly important for the dominant and less dispersible low-frequency bending vibration visuals of the panel described in this application. The edge fastening of the damping means may advantageously lead to a panel with a completely framed sheet material, although at least its corners may be. often relatively loose for the necessary panel lengthening in low frequency panel operation. Said fastening may be made with adhesive or self-adhesive materials. Other forms of useful damping, particularly with respect to multiple minor effects and / or intermediate and higher frequencies, may be accomplished by means of a suitable mass or masses attached to the sheet material at predetermined effective center positions in the surface.

The above panel is indeed two-dimensional. The sound energy from the rear of the panel is not strongly phase related to the sound energy from the front of the panel. This brings the advantage of the total sum of the acoustic performance in a given space, the sound energy with a uniform frequency distribution, a limited effect reflecting standing waves and a good reproduction of natural space.

While the sound or radiation from the acoustic panel is largely non-directional, the percentage of phase-related information outside the speaker axis increases. To improve the focusing of artificial stereo listening, positioning the speaker at a height at which images are usually hung, i.e. at the usual height of a standing person, gives the normal seated listener optimal stereo listening even when in a position slightly deviated from the axis speaker. This triangular left / right geometry relative to the listener provides an additional angular component. This gives a good stereo effect.

This is another advantage for a group of listeners compared to conventional loudspeaker reproduction. Given the truly dispersed nature of the acoustic panel of the acoustic panel, the acoustic panel provides a loud volume, to which the rule of the loss of square distance to the equivalent point source in no way applies. As a result, for a listener sitting off the axis of the speakers, or at a location not very suitable for listening, the panel speaker field strength enhances a better stereo effect compared to conventional speakers. This is because the listener located outside the center of action of all speakers does not suffer from two drawbacks, which are usually applied near the speakers. The first of these is that the perceived loudness of the nearby speaker is excessively increased and, as a consequence of the latter, the perceived loudness of the other speakers.

Another advantage of the flat, lightweight panel loudspeaker is its visual attractiveness, good sound quality and the requirement for only one transducer, this loudspeaker requiring no crossover over the entire sound range per panel diaphragm.

Fig. 3 to 6 illustrate a portable compact disc player 41 having a body 85 provided with a slot 82 through which discs are inserted into or removed from the player, and control buttons 137 through which the player is operated. This player 41 is provided with a pair of opposed speakers 81, which are in the form of thin panel elements 40 and are hinged on opposite sides of the player 41 such that, in the non-operative position, the player 41 is disposed between these speakers. The loudspeakers 40 are sized to match the size of the player, and are hung on the body of the player so as to be rotatable from the inoperative or tilted position shown in FIG. 3 to the functional or exploded position shown in FIG. 4, wherein the directions of rotation of these speakers are shown by arrows C. In the unfolded position, the body 85 of the player 41 tends to function as a central compartment separating the two speakers 40, which improves the separation of the individual channels.

Each of the panel loudspeakers 40 is in the form of a distributed mode acoustic radiator of the same type as described with reference to FIGS. 1a. FIG. 6 and 7 illustrate another embodiment of a portable CD player 41 comprising a body 85 supporting a plate 86, control buttons 137 and a lid 139 that is hinged on the body such that it is rotatable along the arrow D and able to close the plate by overlapping it.

The player 41 is provided with a pair of opposed loudspeakers 81 in the form of thin panel elements 40 that can be hinged on opposite sides of the lid 139 so as to be movable, as shown by the arrow E, from a nonfunctional or tilted position (not shown) to a functional or unfolded position. Alternatively, the loudspeakers may take the form of thin panel elements 39 which may be hidden in a slot (not shown) at the lid 139 and capable of sliding, as shown by the arrow F, between a functional or extended position and a non-functional or retracted position.

Each of the panel loudspeakers 39, 40 is in the form of a distributed mode acoustic radiator of the same type as described with reference to FIG. Thus, each of the two speakers comprises a rigid lightweight panel 2 formed by a cell core 22 surrounded by shells 21, which panel is fixed in a surrounding resilient hinge 3 made, e.g. of foam rubber and fixed in a light rectangular frame 1, e.g. made of plastic. In order to obtain the bending waveform in the panel 2 to cause its resonance to achieve an acoustic output, a transducer 9 is mounted on each of the two panels 2, e.g. of the same type as described with reference to related international applications WO97 / 09859, WO97 / 09861, WO97 / 09858. This transducer 9 is positioned on the respective panels 2 at predetermined positions as described in International Patent Application WO97 / 09842.

Claims (7)

A portable compact disc player comprising a pair of opposed speakers 81 attached to said player, each of said speakers having an element (2) having the ability to dampen and propagate the input vibration energy by bending waves in at least one functional area of the running transversely to its thickness so as to have resonant bending vibration modes distributed over at least one surface and predetermined preferred positions within the surface for the converter means, and a transducer (9) mounted on the member in one of said vibration positions of the member the resonance of the acoustic radiator element which provides the acoustic output during its resonance. A portable compact disc player according to claim 1, characterized in that it comprises a body (85) having a plate (86) and a lid (139) adapted to close the plate by overlapping it, with speakers (81) attached to the lid. . Portable CD player according to claim 2, characterized in that the speakers are hinged on the lid. A portable player characterized in that it is housed in a compact slot in that in the lid there is (81) between a non-functioning position in which the discs according to claim 2, each of the speakers (139) to slide each of the speakers substantially completely hidden in the slot. and a functional position in which the speakers are arranged on opposite sides of the lid. Portable compact disc player according to one of the preceding claims, characterized in that each radiator (2) comprises a rigid light panel with a cell core (22) interposed between the opposing shells (21). Portable compact disc player according to claim 5, characterized in that the radiator (2) is carried in the surrounding frame (1). Portable CD player according to claim 6, characterized in that a flexible hinge (3) is arranged between the frame and the radiator.