WO2001054454A2

WO2001054454A2 - Display apparatus with flat panel loudspeaker

Info

Publication number: WO2001054454A2
Application number: PCT/GB2001/000209
Authority: WO
Inventors: Richard Mark Newlove
Original assignee: Amina Technologies Limited
Priority date: 2000-01-20
Filing date: 2001-01-19
Publication date: 2001-07-26
Also published as: GB2360387A; AU2001228630A1; WO2001054454A3; GB0101400D0

Abstract

Display apparatus (10) comprises a flat panel loudspeaker (12) and a visual display board (14) positioned in front of the flat panel loudspeaker (12). The loudspeaker (12) and visual display board (14) are retained in frame (20). Sound generated by the flat panel loudspeaker (12) may be heard by an observer (30) despite the disposition of the visual display board (14) therebetween. In this way, the observer (30) may view and hear complementary information from the display apparatus. The visual display board (14) may be removed readily from the display apparatus (10) and replaced by new visual display board showing different information, without having to dismantle any part of the flat panel loudspeaker (12).

Description

TITLE: DISPLAY APPARATUS

DESCRIPTION

TECHNICAL FIELD The present invention relates to display apparatus, particularly - but not exclusively - for pomt-of-sale applications m supermarkets and the like. The display apparatus may also, for example, be used m domestic situations or even exhibitions and the like. BACKGROUND ART

It is known to conceal a conventional (pistonic) loudspeaker behind a screen displaying a picture. United Kingdom patent specifications GB 298818 and GB 941944 each disclose arrangements where a loudspeaker is provided m an open-top box-like housing, with the loudspeaker drive unit concealed behind a "lid" comprising a textile fabric. The textile fabric provides a substrate for the picture image and is held taut over the housing or supported by a perforated plate. It is also known from US patent number 4,566,557 to conceal a loudspeaker behind a cover functioning as a direct wave attenuator. The cover only permits high frequency sound to pass therethrough; lower frequencies must pass around the cover m a diffuse manner. The advantages of flat panel loudspeakers, and particularly those comprising a distributed mode acoustic radiator as disclosed m International patent application published under WO97/09842 (the whole contents of which are incorporated herein by reference) , are well documented. It has already been proposed to use such loudspeakers m visual display apparatus comprising a notice or the like board to which notices or the like can be fixed e.g. with pins (see International patent application published under WO97/09848) .

According to the teachings of O97/09848, the visual display apparatus is characterised m that the notice or the like board is a member having capability to sustain and propagate input vibrational energy by bending waves m at least one operative area extending transversely of thickness to have resonant mode vibration components distributed over said at least one area and having predetermined preferential locations or sites withm said area for transducer means and having a transducer mounted wholly and exclusively on said member at one of said locations or sites to vibrate the member to cause it to resonate forming an acoustic radiator which provides an acoustic output when resonating . As described m O97/09848, the flat panel loudspeaker technology can be applied to the design of normal board material commonly used for notices and display advertising, the normal processing of these boards e.g. lamination, screen-printing or spray printing being unhindered. Thus, it is known to incorporate m an advertising display board, a loudspeaker comprising a distributed mode acoustic radiator panel having graphic information e.g. text or pictures of any desired kind printed on the panel . The graphic information can then be supplemented by an audio message via the loudspeaker to reinforce the information presented.

Such a visual display apparatus incorporating a loudspeaker has great potential to pomt-of-sale applications because of the synergistic effect of combining audio and visual advertising. It is believed, for example, that combining a visual sign with a corresponding, localised audible message may help to improve marketing of selected products to consumers at the point of sale. However, supermarkets particularly, the additional cost of setting up such dual advertising is a significant factor, perhaps to the extent that potential benefits may be marginalised. For example, with temporary promotions, it may not be possible to justify the higher cost associated with acquiring and wiring a dedicated loudspeaker display, particularly if an electrician or other skilled or semi-skilled person is required.

The present applicant has appreciated the benefits of using such display apparatus, and has invented a novel arrangement which overcomes or at least alleviates the stated difficulties with known apparatus. DISCLOSURE OF INVENTION In accordance with the present invention, there is provided display apparatus comprising: a flat panel loudspeaker comprising an acoustic radiator and a transducer positioned to excite bending waves the acoustic radiator order to radiate sound; and a visual display board for displaying graphic information, (e.g. text or a picture) ; wherein the visual display board is, use, positioned front of the acoustic radiator, thereby shielding it from view when the visual display board is being viewed. The present applicant has surprisingly found that even though the visual display board represents a substantial physical obstruction m front of the acoustic radiator, sound radiated by the acoustic radiator to persons viewing the visual display board is not significantly impaired. This may be because the visual display board is acoustically coupled to the acoustic radiator, whereby flexural vibrations m the acoustic radiator are passed (directly or indirectly) to the visual display board. With the display apparatus, sound energy is radiated by flexural vibrations propagated across the acoustic radiator, rather than through pistonic movement. The acoustic radiator may be a distributed mode acoustic radiator, as described WO97/09842. The visual display board may have a capability to sustain and propagate bending wave energy and generate sound from action of bending waves. The visual display board may thus behave as a passive acoustic device (see WO97/09842) . In this way, the acoustic radiator may induce flexural vibrations m the visual display board, causing the latter to radiate sound. The visual display board may comprise a material selected from the group consisting of paper, card and cardboard, and even more complex composite structures, perhaps having a stiff lightweight core (see WO97/09842) .

The visual display board may be spaced from the acoustic radiator, there bemg a gap between the visual display board and the acoustic radiator at least over a part of the opposed surfaces. Fluid (e.g. air) trapped the gap may transmit flexural vibrations m the acoustic radiator to the visual display board. The visual display board may be direct contact with the acoustic radiator m discrete locations, or may be directly coupled (e.g. with Blue Tac) to the acoustic radiator m discrete locations. Direct contact or coupling between the visual display board and acoustic radiator over the entire area of overlap between one of the opposed surfaces may even be preferable . The visual display board may be readily removed from front of the (active) acoustic radiator. In other words, the visual display board may be replaced by, or interchanged with, another visual display board without dismantling the flat panel loudspeaker. In this way, visual display boards may be replaced quickly and by non-technical persons. This could be of great benefit domestic situations and pomt-of-sale applications, e.g. m supermarkets and the like. For example, a key site (e.g. the end of an aisle) could be designated for temporary promotions of selected goods, and the display apparatus permanently installed at such site. As the identity of the goods being promoted is changed, the advertising is changed simply by replacing the visual display board and the audio message played over the flat panel loudspeaker. There would be no need to wire m a replacement loudspeaker, nor would there be a need for the visual display board to be anything other than of standard design. The display apparatus may further comprise a mount, perhaps on adhesive plastic material such as Blue Tac, for mounting the visual display board front of the acoustic radiator. The mount may comprise a frame surrounding some or all the peripheral edges of the acoustic radiator and the visual display board. Such an arrangement would enable the visual display board to be mounted m a frame of the same outward appearance as a conventional picture frame. This may be useful m display apparatus for exhibitions and the like where aesthetics are perhaps more important than pomt-of-sale applications.

In one embodiment, the frame may have groove means for slidably receiving the visual display board. The frame may include a moveable/detachable member, perhaps associated with the groove means, with movement/detachment of the member facilitating insertion/removal of the visual display board without dismantling the remainder of the frame. The moveable/detachable member may, m use, provide a bias urging the visual display board nto intimate physical contact with the acoustic radiator. Alternatively, the frame may have projections defining a recess into which the visual display board is a friction fit. A conventional picture frame may be assembled around the said frame to disguise functionality; the conventional picture frame may even be easily removable to facilitate replacement of the visual display board. In either case, the visual display board may be readily removed, either by sliding it out of the frame, or by prising it from the frame, so that a new visual display board may be mounted its place.

The display apparatus may further comprise a backing- board mounted behind the acoustic radiator, thereby sandwiching the acoustic radiator between the visual display board and the backing-board. The backing-board may be useful if both the front and rear surfaces of the display apparatus are visible during use, e.g. if suspended from the ceiling. The backing-board may be plain or may display graphic information. In the latter case, the backing-board may be readily replaceable m the same way as the visual display board.

The acoustic radiator used the present invention is bi-directional . The sound energy radiated from the back is not strongly phase related to that from the front. Thus, a person approaching the acoustic radiator from either the front or the back would hear the sound being reproduced by the flat panel loudspeaker. Accordingly, 'double-sided' audio-visual displays are attainable with the present invention.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the invention will now be described by way of example with reference to the accompanying figures:

Figure 1 which shows a schematic perspective view of a display apparatus according to a first embodiment of the present invention;

Figure 2 which shows a schematic perspective view of display apparatus according to a second embodiment of the present invention; and Figures 3a and 3b which show schematic perspective views of display apparatus according to a third embodiment of the present invention. BEST MODES FOR CARRYING OUT THE INVENTION

Figure 1 illustrates display apparatus (10) comprising a flat panel loudspeaker (12) and a visual display board

(14) registered m front of the loudspeaker (12) . (The visual display board is shown m phantom lines for the sake of clarity) . The flat panel loudspeaker (12) comprises an acoustic radiator (16) and at least one transducer (18) positioned to excite bending waves m the acoustic radiator (16) m order to radiate sound. The flat panel loudspeaker (12) per se is known the art, for example from the teachings of WO97/09842 and thus further description is unnecessary. The visual display board (14) has graphic information (text or pictures - not shown) displayed upon

The acoustic radiator (16) is mounted m a frame (20) which is deeper than the acoustic radiator (16) itself. Frame (20) has an opening (22) m the top of the display apparatus, and grooves (24) are provided on the inner surfaces of the frame members (26) , either side of the acoustic radiator (16) . Through the opening (22), the visual display board (14) is inserted into the grooves (24) until it rests on the bottom frame member (28) . There is contact between the opposed surfaces of the visual display board (14) and acoustic radiator (16), at least m discrete locations. The visual display board (14) is positioned wholly m front of the acoustic radiator (16) m the frame

(20) such that the acoustic radiator (16) is obscured from view when graphic information displayed on the visual display board (14) is bemg viewed. In use, an observer

(30) viewing the visual display board (14) would hear an audio message radiating from the acoustic radiator (16) , despite the fact that the visual display board (14) represents a substantial physical obstruction between the observer and the flat panel loudspeaker (12) .

If the visual display is to be altered (perhaps m combination with the audio message bemg reproduced by the flat panel loudspeaker (12)), all that is required is to replace the visual display board (14) with one of a modified graphic design. This may be achieved simply by sliding out the original visual display board (14) and inserting the one with the modified graphic design. There is no need to dismantle the flat panel loudspeaker (12) m order to alter the visual display. The display apparatus (10 ') illustrated m Figure 2 is perhaps better suited to use m exhibitions than the Figure 1 embodiment. This is because, m use, the frame (20') conceals the uppermost edges of the flat panel loudspeaker (12' ) and visual display board (14'), thus giving the outward impression of a conventional picture frame. Nevertheless, the frame (20') provides for quick and easy changing of the visual display board (14') due to the moveable frame member (50) . As illustrated, moveable frame member (50) is hmged at one end, permitting rotation around axis A. (In an alternative arrangement, the frame member (50) may be readily detachable from the remainder of the frame) . When the visual display board (14') is to be replaced, the frame member (50) is rotated around axis A from its operative position shown phantom lines to allow full access to the framed contents. The original visual display board is removed and a replacement slotted into the vacant space. The frame member (50) may then be rotated back to its operative position, where it is held m place by a catch (not shown) . (If the frame member (50) is detachable instead of hmged at one end, catches may need to be provided at both ends m order to secure the frame together) .

Yet another display apparatus (10") embodying the present invention is illustrated Figures 3a and 3b. As shown m Figure 3a, the display apparatus (10") comprises a frame 20" including two pairs of opposed clips (60,61), with each clip (60) configured to engage the visual display board (13") adjacent a respective edge (62) . Each clip (60) includes a moveable part (64) , which m use is biased m a first position (Figure 3a) for retaining the visual display board (14") the frame (20") . However, the movable parts (64) may be urged m direction of arrows A into a second position (Figure 3b) where they no longer engage the visual display board (14") . Once the movable parts (64) are m the second position, the visual display board (14") may be removed from the frame (20") (possibly by flexing), exposing the acoustic radiator (16") . A replacement visual display board may be inserted into the frame (20") and the movable parts (64) may be urged m direction of arrows B back into the first position.

Claims

CLAIMS 1. Display apparatus comprising: a flat panel loudspeaker comprising an acoustic radiator and a transducer positioned to excite bending waves m the acoustic radiator m order to radiate sound; and a visual display board for displaying graphic information, (e.g. text or a picture); wherein the visual display board is, m use, positioned m front of the acoustic radiator, thereby shielding it from view when the visual display board is being viewed.

2. Display apparatus according to claim 1, m which the visual display board is acoustically coupled to the acoustic radiator.

3. Display apparatus according to claim 1 or 2, m which the visual display board has a capability to sustain and propagate bending waves and generate sound from action of bending waves.

4. Display apparatus according to any one of claims 1 to 3, m which the acoustic radiator is positioned to excite bending wave vibrations m the visual display board for producing an acoustic output therefrom.

5. Display board accordmg to any one of the preceding claims, m which the visual display board is spaced from the acoustic radiator, there being a gap between the visual display board and the acoustic radiator at least over a part of the opposed surfaces.

6. Display board according to claim 5, m which the visual display board is m direct contact with the acoustic radiator m discrete locations, or is directly coupled (e.g. with Blue Tac) to the acoustic radiator m discrete locations .

7. Display board according to any one of claims 1 to 4 , m which there is direct contact or coupling between the

5 visual display board and acoustic radiator over the entire area of one of the opposed surfaces .

8. Display board according to any one of the preceding claims, m which the visual display board is readily removeable from m front of the acoustic radiator.

10 9. Display apparatus according to any one of the preceding claims, further comprising a mount for mounting the visual display board m front of the acoustic radiator.

10. Display apparatus according to claim 9, m which the mount comprises a frame surrounding at least two peripheral

15 edges of the acoustic radiator.

11. Display apparatus according to claim 10, which the frame has groove means for slidably receiving the visual display board.

12. Display apparatus according to claim 10 or 11, m 20 which the frame comprises a moveable member for facilitating removal of the visual display board.

13. Display board accordmg to claim 10, m which the frame has projections defining a recess into which the visual display board is a friction fit .

25 14. Display apparatus according to any one of the preceding claims, further comprising a backing-board mounted behind the acoustic radiator, thereby sandwiching the acoustic radiator between the visual display board and the backing-board.

15. Display apparatus according to claim 14, in which the backing-board is readily replaceable in the same way as the visual display board.

16. Display apparatus according to claim 14 or 15, in which the backing board is acoustically coupled to the acoustic radiator.