GB2155684A - Optically readable storage disc - Google Patents
Optically readable storage disc Download PDFInfo
- Publication number
- GB2155684A GB2155684A GB08503678A GB8503678A GB2155684A GB 2155684 A GB2155684 A GB 2155684A GB 08503678 A GB08503678 A GB 08503678A GB 8503678 A GB8503678 A GB 8503678A GB 2155684 A GB2155684 A GB 2155684A
- Authority
- GB
- United Kingdom
- Prior art keywords
- substrate
- periphery
- storage disc
- cover
- annular
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000003860 storage Methods 0.000 title claims abstract description 72
- 239000000758 substrate Substances 0.000 claims abstract description 95
- 230000001681 protective effect Effects 0.000 claims abstract description 54
- 239000000463 material Substances 0.000 claims abstract description 10
- 239000000853 adhesive Substances 0.000 claims description 15
- 230000001070 adhesive effect Effects 0.000 claims description 15
- 230000005855 radiation Effects 0.000 claims description 6
- 125000006850 spacer group Chemical group 0.000 abstract description 10
- 238000010276 construction Methods 0.000 abstract description 3
- 230000008646 thermal stress Effects 0.000 abstract description 3
- 239000010410 layer Substances 0.000 abstract 2
- 239000012790 adhesive layer Substances 0.000 abstract 1
- 230000003287 optical effect Effects 0.000 description 6
- 239000004033 plastic Substances 0.000 description 6
- 229920003023 plastic Polymers 0.000 description 6
- 230000035939 shock Effects 0.000 description 6
- 230000035882 stress Effects 0.000 description 6
- 239000004411 aluminium Substances 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 4
- 239000011521 glass Substances 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000002093 peripheral effect Effects 0.000 description 3
- 229920005549 butyl rubber Polymers 0.000 description 2
- 238000013016 damping Methods 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 239000000806 elastomer Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000006748 scratching Methods 0.000 description 2
- 230000002393 scratching effect Effects 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 239000013536 elastomeric material Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/24097—Structures for detection, control, recording operation or replay operation; Special shapes or structures for centering or eccentricity prevention; Arrangements for testing, inspecting or evaluating; Containers, cartridges or cassettes
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/24015—Air-sandwiched discs
Landscapes
- Optical Record Carriers And Manufacture Thereof (AREA)
- Packaging For Recording Disks (AREA)
Abstract
An optically readable storage disc comprises a transparent substrate (21) with a recording layer (22) on it, and a cover (25) which is peripherally connected to the substrate and spaced from it by an annular spacer (26) with an adhesive layer to form a sealed space (24) in which the recording layer is situated. A protective annular rim (25) formed integrally with the spacer projects beyond the edge of the substrate to protect this edge, which is vulnerable to impact forces and thermal stresses. Between the edge of the substrate and the periphery of the protective rim, a space or spaces (212, 213) exists or exist in which there are no means which could transmit undesirably large forces in the event of deformation of the protective rim (readily deformable material may be present). Such forces are transmitted by the spacer (26) to the side only of the substrate. Slits or apertures may be provided in the circumferential protective means to assist deformation. Small balancing masses may be provided. Alternative constructions are detailed (Figs. 1,3,4). Thermal stresses are also considered. <IMAGE>
Description
SPECIFICATION
Optically readable storage disc
The invention relates to an optically readable storage disc which comprises a flat transparent substrate with flat sides and a circular periphery, a recording layer which can be modified locally by means of a radiation beam and which is situated on a flat side of the substrate, a cover which has a circular periphery and which is secured to the substrate by annular means with adhesive means which are interposed between the substrate and the annular means, the cover or a portion thereof being spaced from at least that part of the recording layer near the periphery and in such a manner that a sealed space is enclosed between the substrate and the cover, and circumferential protective means which form part of the annular means and which have a periphery with a diameter which is larger than that of the periphery of the substrate.
Such a storage disc is disclosed in, for example, Japanese Patent Application JP-PA 57-74842 (Patents Abstracts of Japan), Vol.
6, No. 156 (P-i 35) (1034), August 1982.
This known storage disc comprises two flat disc members and annular means formed by concentric inner and outer annular spacers which are interposed between said disc members near a centre hole and near the outer circumference of the storage disc to affix said disc members to each other by means of an adhesive. The outer annular spacer comprises circumferential protective means in the form of a cylindrical mounting ring which extends transversely of the interposed portion and between which the two flat disc members are mounted.
Optical storage discs have a very high information-storage capacity. For example, a storage disc having a diameter of 30 cm can store approximately one giga-bit of information on each recording side. Once the storage disc has been provided with information the value of the storage disc is no longer equal to the price of a blank storage disc but rather depends on the importance of the information stored on it. Loss of recorded information may have serious consequences.
In optical storage discs the substrate should be of a high optical quality. Moreover, the substrate should comply with some other requirements depending on the radiation-sensitive material used. Currently, substrates of hard glass (see U.S.-P.S. 4,074,282) or of a high-quality plastics such as polymethylmetacrylate or polycarbonate are often used. Both the hard-glass substrates and the plastics substrates are susceptible to damage by forces acting on the outer rim, in the plane of the substrate, or impact forces. However, the storage disc is not unlikely to be subjected to such impact forces, for example if the storage disc inadvertently slips out of the hands of the user or if during handling the storage disc strikes against objects in its proximity.Moreover, allowance must be made for the fact that storage discs of the type discussed here are usually intended for filing purposes, which means that a service life of at least 10 years is required. During this long period the storage disc may have to be handled many times.
Despite the presence of the mounting ring the known storage disc is not protected adequately against damage by external forces acting on, for example, the outer rim and caused by falling or shocks, even if the storage disc is accommodated in a cassette. This is because the impact forces are transmitted directly to the disc members via the cylindrical mounting ring in which they are mounted.
The likelihood of damage to the storage disc is not always minimized by accommodating the storage disc in a cassette. This is because the cassette itself has also a certain mass. If the cassette is readily deformable the impact load exerted on the rim of the storage disc may be even larger than in the absence of a cassette. However, the cassette does provide satisfactory protection against damage due to forces which act perpendicularly to the plane of the storage disc.
Another disadvantage of the known storage disc is that it may happen that the substrate fractures when the storage disc is subjected to a thermal cycle. This is because at its circumference the glass substrate is mounted in the cylindrical mounting ring which will not expand to the same extent as the substrate during said thermal cycle. For example, if the mounting ring is made of a metal, this may result in the periphery of the substrate being subjected to substantial forces.
It is an object of the present invention to mitigate the drawbacks of the known storage disc.
According to the invention there is provided an optically readable storage disc which comprises a flat transparent substrate with flat sides and a circular periphery, a recording layer which can be modified locally by means of a radiation beam and which is situated on a flat side of the substrate, a cover which has a circular periphery and which is secured to the substrate by annular means with adhesive means which are interposed between the substrate and the annular means, the cover or a portion thereof being spaced from at least that part of the reocrding layer near the periphery and in such a manner that a sealed space is enclosed between the substrate and the cover, and circumferential protective means which form part of the annular means and which have a periphery with a diameter which is larger than that of the periphery of the substrate, wherein between the periphery of the substrate and the periphery of the circumferential protective means a space exists which is substantially free of intermediate means which in the event of deformation of the periphery of the circumferential protective means could transmit to the periphery of the substrate a force which is directed towards the centre of the substrate and which has a magnitude such that it could damage the substrate.
In many cases it will be preferred if the space between the periphery of the substrate and the periphery of the circumferential protective means is completely void. In the event of deformation of the circumferential protective means this ensures that no forces at all can be exerted on the periphery of the substrate. However, it is also conceivable that said space is filled with a readily deformable material.
If the circumferential protective means of the storage disc in accordance with the invention is subjected to shocks at its periphery, these shocks are not transmitted to the periphery of the substrate but, via the annular means, to a flat side of the substrate, namely by shear stresses in the adhesive means between the substrate and the annular means.
Adhesive means such as layers of adhesive, as is known, can withstand shear stresses comparatively well. Since the annular means are very rigid in the plane in which they are situated, the forces exerted on the substrate via the adhesive means will be distributed over the entire area or at least a part of the area covered by the adhesive means.
In one embodiment of the invention said annular means and circumferential protective means together constitute a flat ring having an outer diameter which is larger than the diameter of the substrate. This embodiment has several advantages. The combination of annular means and circumferential protective means has the simplest shape, namely that of a flat ring. The mass of these means is minimal, which may be important in order to minimize the mass inertia and the mass eccentricity of a rapidly rotating storage disc.
There are no portions projecting from that side of the substrate which should face the optical write unit of an apparatus. Thus, contact between the circumferential protective means on a rotating storage disc and the write unit is precluded.
However, it is alternatively possible to employ a combination of annular means and circumferential protective means having a cross-section in the form of, for example, a letter T lying on its side, as in the known storage disc, or a letter L lying on its side.
Through plastic deformation the additional portions thereby formed at the periphery of the circumferential protective means may contribute substantially to the absorption of impact energy, particularly if this impact force acts obliquely on the substrate.
Storage discs which are not accommodated in cassettes may be employed for simple applications. Then, and also in other cases, it may be advantageous to use an embodiment of the invention wherein the circumferential protective means comprise portions which extend aound the outer circumference of the substrate and over the flat side of the substrate opposite the annular means. This may result in the movement of the optical devices with which the storage disc cooperates being obstructed but this is not necessarily always so, particularly if the associated apparatus is constructed to allow for this particular construction of the circumferential protective means. In this embodiment the circumferential protective means of the storage disc is dropped in a direction perpendicular to its surface. It also protects the substrate surface against scratching when the storage disc is laid down.
If the storage disc is of a type in which the cover is made of a different material from that of the substrate, it may be advantageous to use a further embodiment of the invention wherein the cover has a larger diameter than the substrate and in which the portion of the cover which projects from the substrate serves as the circumferential means. The cover may be made of, for example, a thin aluminium sheet material. Such a material is particularly suitable for absorbing local shocks because it has a comparatively low resistance to plastic deformation and can thus absorb the impact energy.
Embodiments of the invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a perspective view, partly in section, of a storage disc which is a first embodiment of the invention,
Figure 2 is a similar view of a second embodment of the invention,
Figure 3 is a similar view of a third embodiment of the invention, and
Figure 4 is a similar view of a fourth embodiment of the invention.
In the various Figures corresponding parts bear the same reference numerals with the
Figure numbers prefixed thereto.
The optically readable storage disc shown in
Fig. 1 comprises a transparent substrate 11 having flat sides 17 and 18 and a circular periphery 19. The flat side 17 carries a recording layer 12 which can be modified locally by means of a radiation beam. Spaced from the recording layer 12 is a cover 13 which also has a circular periphery and which is secured to the substrate 11 by annular means comprising an annular spacer 16, so as to form a sealed space 14 enclosed between the substrate and the cover. Around the circumference of the storage disc, circumferential protective means in the form of a protective annular rim 15 are provided for protecting the substrate 11 against damage by external forces which act in the plane of the storage disc.Together the annular spacer 16 and the protective rim 15 constitute a completely flat ring with a circumferential wall 110 at its outer periphery. Between the wall 110 at the periphery of the protective rim 15 and the outer periphery 19 of the substrate there are no means which could transmit forces which act on the outer wall 110 to the periphery 19 of the substrate. The storage disc shown in Fig. 2 is of a type in which the substrate 11 and the cover 13 have the same diameter and are secured to each other at their peripheries by the interposed annular spacer 16 with adhesive means, for example, a layer of adhesive. Near the centre another annular spacer 17 is interposed between the substrate and the cover.The cover 13 comprises a transparent substrate which is identical to the substrate 11 and which in the same way as the substrate 11 has been provided with a recording layer, not shown. As a result of this a double-sided storage disc is obtained and each of the two substrates constitutes a cover for the other substrate.
Fig. 2 shows a modification of the storage disc shown in Fig. 1. At its periphery the protective rim 25 is provided with cylindrical flange portions 25A which extend perpendicularly to the flat portion of the rim. In Fig. 2 these portions form a cylindrical ring which surrounds the storage disc. Both the protective rim 15 of the storage disc shown in Fig.
1 and the protective rim 25 of the storage disc shown in Fig. 2 have symmetrical crosssectional shapes. This has advantages with respect to quantity-production of the storage disc. Such annular products can be manufactured, for example, by means of an impactextrusion process employing an annular preform of butt-welded aluminium wire. The symmetrical cross-sectional shape of the annular product thus formed minimizes the risk of warping due to inevitable internal stresses.
Another advantage is that the overall mass distribution of the storage disc remains symmetrical. The cylindrical ring 25A in Fig. 2 has an overall axial dimension which is smaller than the distance between the outer surfaces of the substrate 21 and cover 23.
Therefore, the protective rim will not obstruct the movement of the optical recording and reproducing means of an apparatus on which the storage disc is to be used. Obviously the same applies to the protective rim of the storage disc shown in Fig. 1. In principle, it is possible to give the protective rim a different cross-sectional shape which may be symmetrical or asymmetrical. If the cross-sectional shape of the protective rim 25 shown in Fig.
2 is likened to the shape of a letter T lying on its side, alternative shapes which may be used have the form of a letter L, Y or W lying on its side. A protective rim with the cylindrical ring 25A is better capable of absorbing impact energy acting on the circumference of the storage disc. A part of the energy can then be absorbed by plastic deformation of the cylindrical ring. Moreover, owing to the presence of this ring a better protection is obtained against external impact forces which do not act exactly in the plane of the storage disc but which are directed obliquely relatively to this plane. External impact forces on the protective rim 15 or the protective rim 25 give rise to shear stresses in the layers of adhesive between the spacer 16 and 26, respectively, and the substrate 11 and 21 and cover 13 and 23, respectively.In general, layers of an adhesive are much better capable of withstanding shear stresses than tensile stresses, so that in such cases the layers of adhesive are subjected to comparatively favourable loads. The annular spaces 212 and 213 formed between the peripheries 29 and 214 of the substrate 21 and cover 23, respectively, and the flange portions 25A of the protective rim 25 may be filled, if desired, with a material which cannot transmit undesirably large forces.
The storage disc shown in Fig. 3 is of a different construction from those shown in
Figs. 1 and 2. The storage disc comprises a single transparent substrate 31 provided with a radiation-sensitive layer 32. The cover 33 is made from thin aluminium sheet and has an annular raised portion extending over the recording layer 32 to form with the substrate 31 a sealed space 34. Outwardly of this raised portion the cover 33 has a peripheral portion 36 which constitutes the annular means by which the cover is secured to the substrate, the portion 36 being fixed to the substrate by means of an adhesive. At its edge the portion 36 has a channel-section lip 35 which projects beyond and is sprung over the edge of the substrate and which forms the circumferential protective means of the storage disc.The aluminium sheet material used is thin and is not in direct contact with the circumferential wall 39 at the edge of the substrate. Thus, impact energy acting on the circumference of the storage disc will be absorbed by deformation of the circumferential protective means 35. Additional protection is provided by a channel-section elastic ring 315, which fits over the channel-section lip forming the protective means 35. This has the additional advantage that the external surface 318 of the sustrate 31 is protected against scratching when the storage disc is placed with the substrate facing downwards. This may happen in particular in the case of storage discs of a simpler type, for example those intended for use in peripheral equipment of small office computers, personal computers or home computers, when the storage disc is not accommodated in a cassette.The ring 315 may be made of an elastomeric material, preferably a material with optimum damping properties. Specific elastomers such as butyl rubber have suitable properties in this respect.
Another possibility of providing a storage disc resembling that shown in Fig. 3 with circumferential protective means is shown in
Fig. 4. The storage disc shown in this Figure is practically identical to that shown in Fig. 3 except for a modification at the circumference.
The peripheral portion of the cover 43 which is fixed to the substrate 41 does not have a channel-section lip sprung over the edge of the substrate; it projects beyond this edge and is formed with a cylindrical flange portion 45A which is spaced from the edge of the substrate.
Various modifications are possible within the scope of the present invention. It is always preferred to provide an optimum protection of the periphery of the substrate by absorbing shocks through the circumferential protective means. Care must be taken that these protective means cannot give rise to thermal stresses in the substrate. Plastic deformation of the circumferential protective means is a method of aborbing the energy of a shock. However, it is essential that the transmission of forces to the periphery of the substrate is precluded by so constructing the circumferential protective means that a space exists between the periphery of these means and the periphery of the substrate and that this space does not contain any means which can transmit undesirably large impact forces.
All forces, or practically all forces, are transmitted to a flat side or to both flat sides of the substrate or substrates. The circumferential protective means may be modified by providing slits or apertures so that these means may be deformed more easily. Thus, instead of providing circumferential protective means having a continuous periphery, the periphery may be divided into a plurality of parts which may each be deformed individually. Any resulting remaining deformation of the circumferential protective means will generally not interfere with further use of the storage disc and is certainly preferable over damage to the substrate. If necessary, it is often possible to restore at least approximately damaged circumferential protective means to the original shape. Elastic deformation may provide additional protection. A storage disc which drops on its circumference may bounce back and subsequently come down in a less undesirable orientation. Some elastomers such as the aforementioned butyl rubber, are well known for their damping and consequently shock-absorbing properties, so that they are suitable for the present purpose.
The circumferential protective means of the storage disc in accordance with the invention may also be used for balancing the storage disc when necessary. This potential use forms the subject of the Applicants' United Kingdom
Patent Application . . (PHN 10944) filed simultaneously with the present application.
Small local balancing masses may be provided, which could locally transmit impact forces from the circumference to the substrate. Although this is preferably precluded, such a small risk may be acceptable.
Claims (5)
1. An optically readable storage disc which comprises a flat transparent substrate with flat sides and a circular periphery, a recording layer which can be modified locally by means of a radiation beam and which is situated on a flat side of the substrate, a cover which has a circular periphery and which is secured to the substrate by annular means with adhesive means which are interposed between the substrate and the annular means, the cover or a portion thereof being spaced from at least that part of the recording layer near the periphery and in such a manner that a sealed space is enclosed between the substrate and the cover, and circumferential protective means which form part of the annular means and which have a periphery with a diameter which is larger than that of the periphery of the substrate, wherein between the periphery of the substrate and the periphery of the circumferential protective means a space exists which is substantially free of intermediate means which in the event of deformation of the periphery of the circumferential protective means could transmit to the periphery of the substrate a force which is directed towards the centre of the substrate and which has a magnitude such that it could damage the substrate.
2. An optically readable storage disc as claimed in Claim 1, wherein said annular means and circumferential protective means together constitute a flat ring having an outer diameter which is larger than the diameter of the substrate.
3. An optically readable storage disc as claimed in Claim 1, wherein the circumferential protective means comprise portions which extend around the circumference of the sustrate and over the flat side of the substrate opposite the annular means.
4. An optically readable storage disc as claimed in Claim 1 in which the cover is made of a different material from that of the substrate, wherein the cover has a larger diameter than the substrate and the portion of the cover which projects beyond the substrate serves as the circumferential protective means.
5. An optically readable storage disc substantially as herein described with reference to
Fig. 1, 2, 3 or 4 of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL8400476A NL8400476A (en) | 1984-02-14 | 1984-02-14 | OPTICALLY READABLE MEMORY DRIVE. |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8503678D0 GB8503678D0 (en) | 1985-03-13 |
| GB2155684A true GB2155684A (en) | 1985-09-25 |
| GB2155684B GB2155684B (en) | 1988-11-02 |
Family
ID=19843488
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08503678A Expired GB2155684B (en) | 1984-02-14 | 1985-02-13 | Optically readable storage disc |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS60140235U (en) |
| BE (1) | BE901719A (en) |
| CA (1) | CA1241744A (en) |
| DD (1) | DD228381A5 (en) |
| DE (1) | DE3505015A1 (en) |
| ES (1) | ES8606710A1 (en) |
| FR (1) | FR2559607A1 (en) |
| GB (1) | GB2155684B (en) |
| IT (1) | IT1183232B (en) |
| NL (1) | NL8400476A (en) |
| SU (1) | SU1487826A3 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2343784A (en) * | 1998-11-16 | 2000-05-17 | Leung Ching Yuen | Optical disc |
| GB2377074A (en) * | 2001-03-06 | 2002-12-31 | Chieh-Ho Chen | Compact disc having a circumferential edge shaped to prevent cutting a user's hand |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2087129A (en) * | 1980-10-06 | 1982-05-19 | Storage Technology Corp | Information storage disc using radiant energy |
| EP0054640A1 (en) * | 1980-12-19 | 1982-06-30 | International Business Machines Corporation | Composite magnetic recording disk |
| EP0096623A1 (en) * | 1982-06-08 | 1983-12-21 | Thomson-Csf | Protected optical disc with freely mounted layer bearer |
| EP0109245A2 (en) * | 1982-11-10 | 1984-05-23 | Kabushiki Kaisha Toshiba | Radiation sensitive record disc with improved internal structure |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE190908C (en) * | ||||
| DE203656C (en) * | ||||
| GB335768A (en) * | 1929-10-24 | 1930-10-02 | Jacoviac Maurice | Improvements in protecting devices for gramophone disc records |
| DE883811C (en) * | 1951-06-08 | 1953-07-20 | Hermann Geiselhart | Ring made of rubber as plate protection |
| JPS5774842A (en) * | 1980-10-24 | 1982-05-11 | Mitsubishi Electric Corp | Optical information recording disk |
| JPS57150155A (en) * | 1981-03-09 | 1982-09-16 | Matsushita Electric Ind Co Ltd | Magnetooptic disc |
| JPS57172541A (en) * | 1981-04-15 | 1982-10-23 | Toshiba Corp | Information storage medium |
| JPS57172542A (en) * | 1981-04-15 | 1982-10-23 | Toshiba Corp | Information storage medium |
-
1984
- 1984-02-14 NL NL8400476A patent/NL8400476A/en not_active Application Discontinuation
-
1985
- 1985-02-07 CA CA000473768A patent/CA1241744A/en not_active Expired
- 1985-02-11 IT IT19458/85A patent/IT1183232B/en active
- 1985-02-11 ES ES540285A patent/ES8606710A1/en not_active Expired
- 1985-02-12 BE BE0/214507A patent/BE901719A/en not_active IP Right Cessation
- 1985-02-12 FR FR8501934A patent/FR2559607A1/en active Pending
- 1985-02-12 DD DD85273212A patent/DD228381A5/en unknown
- 1985-02-13 GB GB08503678A patent/GB2155684B/en not_active Expired
- 1985-02-13 SU SU853862706A patent/SU1487826A3/en active
- 1985-02-13 JP JP1985017893U patent/JPS60140235U/en active Pending
- 1985-02-14 DE DE19853505015 patent/DE3505015A1/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2087129A (en) * | 1980-10-06 | 1982-05-19 | Storage Technology Corp | Information storage disc using radiant energy |
| EP0054640A1 (en) * | 1980-12-19 | 1982-06-30 | International Business Machines Corporation | Composite magnetic recording disk |
| EP0096623A1 (en) * | 1982-06-08 | 1983-12-21 | Thomson-Csf | Protected optical disc with freely mounted layer bearer |
| EP0109245A2 (en) * | 1982-11-10 | 1984-05-23 | Kabushiki Kaisha Toshiba | Radiation sensitive record disc with improved internal structure |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2343784A (en) * | 1998-11-16 | 2000-05-17 | Leung Ching Yuen | Optical disc |
| GB2343784B (en) * | 1998-11-16 | 2001-08-01 | Leung Ching Yuen | Irregular optical disc |
| GB2377074A (en) * | 2001-03-06 | 2002-12-31 | Chieh-Ho Chen | Compact disc having a circumferential edge shaped to prevent cutting a user's hand |
Also Published As
| Publication number | Publication date |
|---|---|
| NL8400476A (en) | 1985-09-02 |
| DD228381A5 (en) | 1985-10-09 |
| IT8519458A0 (en) | 1985-02-11 |
| CA1241744A (en) | 1988-09-06 |
| GB8503678D0 (en) | 1985-03-13 |
| IT1183232B (en) | 1987-10-15 |
| FR2559607A1 (en) | 1985-08-16 |
| ES8606710A1 (en) | 1986-04-01 |
| SU1487826A3 (en) | 1989-06-15 |
| BE901719A (en) | 1985-08-12 |
| DE3505015A1 (en) | 1985-08-14 |
| JPS60140235U (en) | 1985-09-17 |
| GB2155684B (en) | 1988-11-02 |
| ES540285A0 (en) | 1986-04-01 |
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