GB2449437A

GB2449437A - Mat to cancel or reduce electrostatic charges in media playback discs

Info

Publication number: GB2449437A
Application number: GB0709719A
Authority: GB
Inventors: John David Michael Rogers
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-05-22
Filing date: 2007-05-22
Publication date: 2008-11-26
Also published as: GB0709719D0

Abstract

A media disc playing or recording arrangement comprises one of a complimentary pair of mats adapted to be placed adjacent the media disc as the media disc is inserted in a media disc player or recorder. The mat(s) comprise a lightweight film 1 of a conductive material preferably having a patterned layer 2 of one or more conductive inks printed thereon on one or both sides thereof (Figs. 1 to 3). One such mat has its material polarity at 0{ and the other mat at 180{, and, in the case of a compact disc or any other digital disc playing arrangement, the mats are of a size substantially corresponding to that of the digital disc, especially that of a compact disc. In the case of a vinyl record, the mats are of a size substantially corresponding to that of the record label at the centre of the record but without encroaching on the playing surface. The single mat to be used is selected from the pair dependant upon the material polarity of the media disc in use. The mat acts to counter the effect of any static or electrostatic charge that is built up on the surface of a disc whilst in use.

Description

MeiIb DEw Pinyhig Arrnngements This invention relates to media disc

playing or recording arrangements, and especially to devices for use in such arrangements for improving their S perceived performance.

Media disc include all types of discs on which sound information, with or without pictures or graphics, are inscribed in some way for reading or sensing by reproduction devices, including compact disc, video disc (Digital Versatile Disc or Digital Video Disc, otherwise known as DVD), various types of Compact Disc Read-Only Memory (CD-ROM), other similar digital or optical disc storage devices and playing formats such as Super Audio Compact Disc (SACD) and vinyl records.

The environment inside a compact disc (CD) player is dry and warm because of heat generated by digital circuits and drive motors. The combination ofa dry warm atmosphere and friction in air of the rotating compact disc results in electrostatic charges being generated inside the enclosure, particularly because the compact disc is made of plastic with a very high insulation resistance. The presence of electrostatic charges can directly influence the operation of digital circuits by inducing random switching. This could result in operational failure unless error correction systems allow interpolation of missing data by the processors.

Also, indirect interference can occur in several ways. The electrostatic fields are mobile because of disc movement so that they can couple into transducers being driven by the digital circuits. Again error detection and correction/interpolation techniques often allow the system to keep going but degradation can occur. For these reasons it is worthwhile trying to remove the build up of electrostatic hot spots or at least to even out the distribution of the

electrostatic fields.

The same or very similar conditions are present in the case of the various video disc players, and players of CD-ROM and SACD and other digital formats.

Likewise, problems arise when writing information accurately onto a digital disc using digital recording machines because of the presence of electrostatic charges, which interfere with any or all of the electronic components used for recording purposes.

Although the environment is different, similar problems also arise in the case of vinyl records where electrostatic charges are built up as the record revolves on the turntable, not least due to the friction arising where the central spindle of the record player rotates within the hub assembly. In these cases, the electrostatic charges deflect the movement of the stylus tip as it traces the groove waIls of the record and prevents it from accurately reading or sensing the information embedded in the record.

The aforementioned problems are not new and in the case of compact disc playing arrangements they have been addressed by the design of a mat described in UK Patent GB 2313697.

However, there is a further aspect of media disc playing arrangements, which has not yet been addressed, and which affects the perceived performance.

This is that the polarity of the material used for making the discs and the way that that polarity relates to the orientation of the reading or sensing mechanisms has a significant effect on the retrieval of any sound related information in such a way that the cohesive structure of the resulting sound on reproduction is adversely affected.

No material is actually solid, but it is made up of densities of electromagnetic energy. Eleclrómagnetic energy has a polarity that is particularly pronounced in flat materials where there is a defmite positive and negative side to the material. As a result, when flat material is used in systems for capturing and reproducing electronically recorded sound there is a distinct reduction in the cohesiveness of the sound should any piece of flat material be used with its polarity the wrong way up.

This is especially the case with media discs where about one half of all such discs are manufuctured with their material polarity the wrong way up and therefore have impaired reproduction. In the case of so-called double sided discs, where sound and other information is inscribed on both sides of the disc and both sides can be used for reproduction, though only one side at a time with current technology, one side will inevitably be played the wrong way up with regard to material polarity. Double sided discs typically include vinyl records and a variety of digital discs, especially certain video discs.

With media discs that are not double sided, there is only one way up in which such discs can be read or sensed during playback, and if this requires, for example, the negative 1800 side of the disc to be used uppermost in terms of material polarity in the media disc player, reproduction of any sound information would be impaired during playback. As described aforesaid, this situation also arises with one of the two sides of any double-sided disc, where the playing of one side would require the negative 1800 side of the disc to be used uppermost and the positive 0 side of the disc to be used uppermost when the other side is replayed.

Similar problems, as aforesaid, arise with media discs used with media disc recording arrangements as well as for reproduction.

It is an object of the present invention to provide a pair of devices in the form of two complimentaiy mats for use in media disc playing or recording arrangements and in conjunction with the actual media disc to minimise not only the effects of electrostatic charges that are generated but also the effects of the material polarity of the media disc should it be upside down during playback or recording from the aspect of achieving best performance. One mat would be used if the material polarity of the media disc in use were one way, the other mat if the polarity were the other way up.

According to the present invention there is provided a media disc playing or recording arrangement including, in the case of a digital disc, a pair of complimentary mats of a size substantially corresponding to that of a compact disc and intended to be placed adjacent the media disc as the media disc is inserted in a media disc player or recorder, said mats comprising a flexible film of a conductive material that have a patterned conductive layer so disposed on at least one side thereof as to disperse electrostatic fields across the surface of the media disc during play or recording thereot whereby one of the mats of the complimentary pair would have the material polarity of the conductive film one way (00) and the other mat upside down (180 ). In the case of a vinyl record, where the playing surface to be reproduced is uppermosi; and so as not to obstruct the playing surface, the complimentary pair of mats, as aforesaid, would be of a size similar to that of the record label at the centre of the vinyl record but without encroaching on the playing surface.

In a preferred arrangement according to the present invention said mats have a conductive, patterned layer disposed on both sides thereof, the conductivities of which are the same or different.

Advantageously, the patterns on the two sides of said mats do not overlap.

In one arrangement it may be arranged that said conductive layer includes a square pattern, which optionally may be offset from the centre of said mats.

In carrying out said one arrangement it may be provided that said conductive layer also includes four arc shaped sections each bounded by a straight edge disposed around the circumference of said mat, the straight edge of each of said sections being disposed adjacent a respective one of the sides of said square pattern.

The four arc shaped sections may be circumferentially spaced from one another or may in one or more instances be joined to one another.

Preferably, said square pattern and said four arc shaped sections do not overlap, and are spaced from each other, and may be disposed on the same side of said mats or on opposite sides of said mats.

The present invention also relates to a media disc mat intended for use in any media disc playing arrangement as aforesaid.

Some exemplary embodiments of the invention will now be described, reference being made to the accompanying drawings in which Figs. I to 3 each depict a media disc mat embodying the present invention for use in any media disc playing or recording arrangement embodying the present invention.

The present embodiments of the invention relate to media disc playing arrangements and especially to a device in the form of a complimentary pair of mats for use in a media disc player or recorder and in conjunction with a media disc to minimise the effects of electrostatic charges which are generated both before and as the media disc is played, whereby one mat is used where the material polarity of the uppermost side of the media disc is 00 during playback or recording and the other mat where the material polarity is 1800.

The mats consist of a lightweight flexible film of a conductive material which, in the case of a digital disc is the substantially the same size as a compact disc and which is placed adjacent the digital disc, on the non-playing or recording side thereof, as the digital disc is inserted in the digital disc player. In the case of a vinyl record, where the playing surface is uppermost; and so as not to obstruct the playing surface, the size of the mat would be similar to that of the record label at the centre of the record but without encroaching on the playing surface. Typically the mats consist of a layer of impregnated conductive thermoplastic film that optionally may be transparent. The mats are also provided with an overlying conductive layer, typically conductive ink, which is printed on or otherwise applied to one or both sides of the conductive film material, in some patterned form.

The mat depicted in Fig. 1, one of a complimentary pair, comprises a circular transparent layer 1 of impregnated conductive material on which is printed a patterned layer 2 of a conductive ink. The layer 1 is provided with a central hole 3 through which the driving mechanism of the media disc player or recorder, including digital disc players or recorders and vinyl record players (not shown), extends when the mat is inserted along with a media disc into the media disc player or recorder. The patterned layer 2 consists of an inner square section 4 and four arc shaped sections 5 each bounded by a straight edge 6 disposed around the circumference of the layer 1, the straight edge 6 of each of the arc shaped sections 5 being disposed adjacent a respective one of the sides 7 of the inner square section 4. The inner square section 4 and the four arc shaped sections 5 may be provided on the same side of the layer 1 or may be on opposite sides. The inner square section 4 and the four arc shaped sections 5 may comprise the same or different inks, the conductivities of which are the same or different Also, the patterned sections 4 and 5 may be centrally disposed relative to the hole 3 or may be slightly ofiet. One of the complimentary mats will have the circular transparent layer I of the impregnated conductive material one way up, where the material polarity of the uppermost surface is 00, whereas the other complimentary mat will have the impregnated conductive material the other way up, where the material polarity of the uppermost surface is 1800. Otherwise, the two complimentary mats may appear to look the same aside from an appropriate mark of identification as to which is which, 0 or 1800, with regard to the polarity of the material.

The mat depicted in Fig. 2 of the drawings, one of a complimentary pair, is very similar to that of Fig. 1, except that whereas in Fig. I the arc shaped sections 5 are spaced from one another around the circwnference of the layer 1, in Fig. 2 the arc shaped sections 5 are joined together at their adjacent ends 8. Again, the two complimentary mats may appear to look the same aside from an appropriate mark of identification as to which was which with regard to the polarity of the material, as aforesaid.

The mat depicted in Fig. 3 of the drawings, one of a complimentary pair, is similar to that of Figs. I and 2 except that whereas in Fig 1 the arc shaped sections are spaced from one another around the circumkrence of the layer 1, in Fig. 3 two of the arc shaped sections 5 are joined together at their adjacent ends 8. As with the mats of Figs. 1 and 2, one of the complimentary mats will have the circular transparent layer 1 of the impregnated conductive material one way up, where the material polarity of the uppermost surface is 0 , whereas the other complimentary mat will have the impregnated conductive material the other way up, 180 , as aforesaid. Otherwise, the two complimentary mats may appear to look the same aside from an appropriate mark of identification as to which is which with regard to the polarity of the material, as aforesaid.

The patterned mats which have been described have the effect, in use, of minimising the effects of electrostatic charges which are built up by either reducing the electrostatic charges and/or by causing their effects to be evened out over the surface of the compact disc so that a general improvement in the performance of the compact disc player is achieved.

It will be appreciated that the patterning of the mats of Figs. 1 to 3 has been given by way of example only, and the present invention as claimed extends to similar mats having other patterned sections which will minimise the described effects of electrostatic charges.

The patterned mats described as aforesaid will have indicators showing which have the impregnated conductive material where the material polarity of the uppermost surface is at 0 and which at 180 . By harmonizing the material polarity of the media discs with that of the patterned mats, 00 with 00 uppermost and 180 with 1800 uppermost, not only are the effects of electrostatic charges minimized, as aforesaid, the respective polarities of the electromagnetic energies contained within the media discs are also correctly aligned. g

Claims

(1 AIMS 1. A media disc playing or recording arrangement including a

complimentaiy pair of mats intended to be placed adjacent the media disc during playback, said mats comprising a flexible film of a conductive material which has a patterned conductive layer so disposed on at least one side thereof as to disperse electrostatic fields across the surface of the media disc during play thereof: or during recording, whereby the material polarity of one mat is 00 and the other at 1800 in order to match the material polarity of the media disc according to which side is being played or recorded upon and thereby harmonize their respective electromagnetic energies so as to improve the perceived sound on playback.
2. An arrangement as claimed in claim 1, in which, in the case of a compact disc or any other digital disc playing or recording arrangement, the mats are of a size substantially corresponding to that of the digital disc, especially that of a compact disc, and are placed adjacent the digital disc as the disc is inserted in the disc player or recorder.
3. An arrangement as claimed in claim 1, in which, in the case of a vinyl record, the mats are of a size substantially corresponding to that of the record label at the centre of the record but without encroaching on the playing surface and are placed adjacent the vinyl record ready for play and left there throughout the playback period so that the mat rests on the record label or on any flat device resting on the record label such as an anti-vibration mat.
4. An arrangement as claimed in claims I to 3, in which said mats have a said patterned conductive layer disposed on both sides thereof, the conductivities of which are the same or different.
5. An arrangement as claimed in claim 4, in which the patterns on the two sides of said mats do not overlap.
6. An arrangement as claimed in any of claims 1 to 5, in which said patterned conductive layer includes a square pattern.
7. An arrangement as claimed in claim 6, in which said square pattern is offset from the centre of said mats.
8. An arrangement as claimed in claim 6 or claim 7, in which said patterned conductive layer also includes four arc shaped sections each bounded by a straight edge disposed around the circumference of said mats, the straight edge of each of said sections being disposed adjacent a respective one of the sides of said square pattern.
9. An arrangement as claimed in claim 8, in which the four arc shaped sections are circumferentially spaced from one another.
10. An arrangement as claimed in claim 8, in which the four arc shaped sections are joined to one another.
11. An arrangement as claimed in claim 8, in which two of the four arc shaped sections are joined to one another.
12. An arrangement as claimed in any of claims 8 to 11, in which said square pattern and said four arc shaped sections do not overlap, and are spaced from each other.
13. An arrangement as claimed in any of claims 8 to 12, in which said square pattern and said four arc shaped sections are disposed on the same side of said mats.
14. An arrangement as claimed in any of claims 8 to 12, in which said square pattern and said four arc shaped sections are disposed on opposite sides of said mats.
15. A media disc playing or recording arrangement including a complimentary pair of mats substantially as hereinbefore described with reference to the accompanying drawings.
16. A complimentary pair of media disc mats intended for use in a media disc playing or recording arrangement as claimed in any preceding claim.