Patent Application
20080085019
The Figures are not drawn to scale. Generally, identical components are denoted by the same reference numerals in the Figures.
Such display devices are often provided with means for generating sound. Conventional loudspeakers are generally used to generate sound. Flat panel acoustic transducers are used in the device according to the invention. Such transducers offer advantages over conventional loudspeakers in that they are flat.
It is known, for instance, from International Patent application WO 97/09854 to place panel acoustic transducers 4 next to the display panel in the form of rectangular flat panel loudspeakers that are flush-mounted with the front of the display device. However, for these flat panel loudspeakers, it is necessary that the two long sides of the panel can vibrate freely. This means that these loudspeakers have to be separate parts, rather than part of the front panel itself, which increases the complexity of the device and of its manufacture. Moreover, these separate flat panel loudspeakers are distinguishable as separate parts, which has a distracting effect on the overall impression of the design because slits 5 are clearly visible.
Placing a panel acoustic transducer 6 in front of the display screen 2, using a transparent panel acoustic transducer 6, is known from United States Patent 2003059069, wherein a transparent panel acoustic transducer formed as a transparent front panel is positioned in front of a display screen. The display screen itself may be, for instance, a display screen of a mobile phone, or an LCD or PDP display.
This design, however, has a negative influence on the quality of the image. The transparent acoustic transducer vibrates. Consequently, reflections of lamps and other objects in this front panel also vibrate and thus distract the viewer, because visible artefacts are created. In particular, vibrations of the front panel are visible at low frequencies (<400 Hz) due to the large excursion in the middle of the front panel. Furthermore, the exciters required to generate the sound have to be on the side of the front panel so as to allow the display screen to remain visible, which makes the excitation not very efficient. For this reason, a number of powerful exciters have to be used at each side of the panel. Moreover, much of the power of the rather powerful exciters is not transferred to the panel itself, but to other parts of the display device.
an outer transparent thin panel 6b and
a supporting panel 6a,
wherein
the supporting panel 6a has a considerably larger stiffness than the transparent thin panel 6b, and
the transparent thin panel 6b comprises, at at least one side of the supporting panel, a side area 7 extending beyond the supporting panel 6a, said extending side area 7 being provided with an exciter 8 at a side facing the display screen 2.
The thin panel and the supporting panel are combined to a laminate, i.e. to one construction, with one or more side areas that can vibrate freely, and a middle area that does not vibrate, or vibrates at least to a much smaller extent, due to the stiffness of the supporting panel.
It is to be noted that, within the scope of the invention, the laminate may comprise additional layers, for instance, anti-glare or anti-scratch layers for optical or safety reasons.
With this arrangement, in which the thin panel extends across the supporting panel, there is no visible distinction between the transducer or transducers and the front panel, nor are there visible artefacts, because
the outer thin panel extends across the supporting panel, forming a single front surface, and
the middle part of the front panel does not vibrate or hardly vibrates, thus avoiding visible artefacts.
The transparent thin panel 6b is glued, for instance, on top of the transparent stiff supporting panel 6a. The exciters (8), for making the front panel vibrate, are mounted at the back of the thin panel 6b at the side areas 7.
Different panel materials can be used, as long as they fulfil acoustical and visual requirements.
Useful materials for the transparent thin panel are thin glass and polycarbonate. A useful material for the supporting panel is glass.
The freely vibrating side areas 7 are excited very efficiently, because the side area is provided with an exciter.
The thin panel may have one, but preferably two side areas, each side area being provided with one or more exciters. This increases the maximum attainable loudness and also makes it possible to produce stereo sound.
The supporting panel 6a has such dimensions that it covers the display area, while the thin panel 6b can vibrate freely at the sides. The vibrating area may have a smaller height than the total panel so that the thin panel is fixed at the top and bottom as well, thus leaving only one freely vibrating side.
The supporting panel 6a has a stiffness which is preferably at least three times, more preferably at least five times, and most preferably at least ten times larger than the stiffness of the thin panel 6b.
The following materials may be used for thin panel 6b and supporting panel 6a.
Thin panel 6b: hardened glass with a thickness of between 0.2 and 1 mm, for instance, 0.5 mm, or polycarbonate with a thickness of between 0.4 and 2 mm, for instance, 1 mm, covering a supporting panel 6a of glass or polycarbonate with a thickness of between 2 and 10, preferably between 3 and 7 mm.
In summary, the invention can be described as follows.
A display device 1 comprises a transparent panel acoustic transducer 6. The transparent front panel 6 has a laminate comprising
The supporting panel 6a has a considerably larger stiffness than the transparent thin panel 6b, and the transparent thin panel 6b comprises, at at least one side of the supporting panel, a side area 7 extending beyond the supporting panel 6a, said extending side area 7 being provided with an exciter 8 or a receiver at a side facing the display screen 2.
It will be clear that many variations are possible within the scope of the invention. It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinbefore.
For instance, the laminate of the thin panel and the supporting panel may be provided with a stiffening part which is attached to the supporting panel at one or more peripheral parts of this panel.
Furthermore, the example given above relates to a display device for display screens such as PDP, LCD, etc. Within the scope of the invention, the ‘display screen’ may also be a picture or a painting, in which case the ‘display device’ is, for instance, a frame for a picture with a front plate. For instance, in a museum, paintings may be provided with transparent acoustic transducers of the invention which provide information on the image visible through the transparent acoustical transducers, without distracting from the painting.
The transparent acoustic transducer may be flat or (slightly) curved.
In the example, the transparent acoustic transducer is shown with exciters, i.e. the transducer is used to generate sound. Within the scope of the invention, the side areas or one or more of the side areas may be provided with a receiver. For instance, one or two of the extending side areas may be provided with an exciter to generate sound, and another extending side area may be provided with a receiver. This allows two-way communication, without any visible loudspeakers or microphone.
The invention resides in each and every novel characteristic feature and each and every combination of characteristic features. Reference numerals in the claims do not limit their protective scope. Use of the verb “comprise” and its conjugations does not exclude the presence of elements other than those stated in the claims. Use of the article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements.
| Number | Date | Country | Kind |
|---|---|---|---|
| 04104921.4 | Oct 2004 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB05/53244 | 10/3/2005 | WO | 00 | 4/3/2007 |
