EP1086454A1 - Disc-shaped, optically readable information carrier - Google Patents
Disc-shaped, optically readable information carrierInfo
- Publication number
- EP1086454A1 EP1086454A1 EP99927051A EP99927051A EP1086454A1 EP 1086454 A1 EP1086454 A1 EP 1086454A1 EP 99927051 A EP99927051 A EP 99927051A EP 99927051 A EP99927051 A EP 99927051A EP 1086454 A1 EP1086454 A1 EP 1086454A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- disc
- shaped
- information carrier
- raised portions
- optically readable
- 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.)
- Withdrawn
Links
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
Definitions
- the present invention relates to a disc-shaped, optically readable information carrier made of plastic material, one side of which has an information- containing microstructure and the other side of which has a distance member which projects from the plane of the side and is located radially inside the microstructure .
- each disc In order to prevent the disc products lying one on another in the stack from adhering to each other when they are to be lifted individually from the stack, each disc has on one side a distance member in the form of an annular raised portion located radially inside the information-containing microstructure and on the side opposite the microstructure. In this way, a narrow gap is formed between the disc products, which allows air to penetrate between the latter so that mutual adhesion is prevented.
- this annular raised portion leads to certain phenomena of stress and shrinkage in the plastic material when the disc element hardens directly after pressing.
- This ring and the stress and shrinkage phenomena it causes can in certain cases impart to the finished CD impaired optical characteristics and a less aesthetically pleasing appearance by virtue of the fact that there is an annular discontinuity on the disc side when visually readable printing on this side goes right in towards the centre hole of the disc.
- the continuous, annular raised portion is replaced by a small number of (at least three) point-shaped, uniformly distributed raised portions.
- Fig. 1 is a plan view of a CD disc provided with point- shaped raised portions according to the present invention.
- Fig. 2 is an enlarged cross-sectional view along the line II-II in Fig. 1, showing a further enlarged detail of a raised portion on the disc element.
- Fig. 1 shows an optically readable, disc-shaped information carrier 10, such as what is known as a compact disc or CD.
- the disc 10 is injection-moulded in a known manner in a plastic material, for example polycarbonate, and provided with an information- containing microstructure on one side 12.
- a small number of unobtrusive, point-shaped raised portions 16 are formed (six in the embodiment shown) , distributed uniformly in the circumferential direction.
- the raised portions 16 are positioned concentrically with the centre hole 18 of the disc 10 and located radially inside the microstructured region of the disc.
- These raised portions 16 constitute a basic distance element for keeping newly pressed, stacked CDs slightly apart so as thus to prevent the discs adhering to one another when they are to be lifted individually off the stack.
- the raised portion 16 can suitably be in the form of a truncated cone, with a base diameter of roughly 0.8 mm, a top diameter of roughly 0.6 mm and a height of roughly 0.2 mm or another dimension depending on the desired separation of the discs.
Landscapes
- Optical Record Carriers And Manufacture Thereof (AREA)
- Manufacturing Optical Record Carriers (AREA)
Abstract
The invention relates to a disc-shaped, optically readable information carrier (10) made of plastic material. The disc (10) has a distance member (16) projecting from one side in the form of at least three point-shaped raised portions distributed uniformly in the circumferential direction.
Description
Disc-shaped, optically readable information carrier
The present invention relates to a disc-shaped, optically readable information carrier made of plastic material, one side of which has an information- containing microstructure and the other side of which has a distance member which projects from the plane of the side and is located radially inside the microstructure .
In the production of CD discs, the newly pressed disc products are normally stacked in an intermediate station before they go through further stages of manufacture, such as metallizing, labelling, lacquering etc. In order to prevent the disc products lying one on another in the stack from adhering to each other when they are to be lifted individually from the stack, each disc has on one side a distance member in the form of an annular raised portion located radially inside the information-containing microstructure and on the side opposite the microstructure. In this way, a narrow gap is formed between the disc products, which allows air to penetrate between the latter so that mutual adhesion is prevented.
It has been found that this annular raised portion leads to certain phenomena of stress and shrinkage in the plastic material when the disc element hardens directly after pressing. This ring and the stress and shrinkage phenomena it causes can in certain cases impart to the finished CD impaired optical characteristics and a less aesthetically pleasing appearance by virtue of the fact that there is an annular discontinuity on the disc side when visually readable printing on this side goes right in towards the centre hole of the disc. In order to essentially eliminate this disadvantage in every respect, it is proposed according to the present invention that the continuous, annular raised portion is replaced by a
small number of (at least three) point-shaped, uniformly distributed raised portions. In this connection, it has been found that, in addition to the necessary air gap between the discs in the stack being brought about, the previous stress and shrinkage phenomena virtually disappear also, which results in the optical and aesthetic characteristics of the disc being improved.
Further features of the disc-shaped, optically readable information carrier according to the invention are indicated in the dependent patent claims below.
The invention is described in greater detail below with reference to the appended drawing, in which:
Fig. 1 is a plan view of a CD disc provided with point- shaped raised portions according to the present invention, and
Fig. 2 is an enlarged cross-sectional view along the line II-II in Fig. 1, showing a further enlarged detail of a raised portion on the disc element.
Fig. 1 shows an optically readable, disc-shaped information carrier 10, such as what is known as a compact disc or CD. The disc 10 is injection-moulded in a known manner in a plastic material, for example polycarbonate, and provided with an information- containing microstructure on one side 12. On the opposite side 14 of the disc 10, a small number of unobtrusive, point-shaped raised portions 16 are formed (six in the embodiment shown) , distributed uniformly in the circumferential direction. The raised portions 16 are positioned concentrically with the centre hole 18 of the disc 10 and located radially inside the microstructured region of the disc. These raised portions 16 constitute a basic distance element for keeping newly pressed, stacked CDs slightly apart so as thus to prevent the discs adhering to one another when they are to be lifted individually off the stack.
Suitably, there are six point-shaped raised portions 16, but there can be fewer (at least three) or more. As shown in the enlarged detail in Fig. 2, the raised portion 16 can suitably be in the form of a truncated cone, with a base diameter of roughly 0.8 mm, a top diameter of roughly 0.6 mm and a height of roughly 0.2 mm or another dimension depending on the desired separation of the discs. It has been found that it is possible to eliminate shrinkage and stress phenomena which occurred previously in connection with a continuous annular raised portion as the distance element, which had a negative effect on the optical characteristics of the finished disc and to some extent on its appearance in the form of streaks caused by displaced air from the mould cavity for the circular distance ring.
Claims
1. Disc-shaped, optically readable information carrier made of plastic material, one side (12) of which has an information-carrying microstructure, and the other side (14) of which has a distance member (16) which projects from the plane of the side and is located radially inside the microstructure, characterized in that distance member (16) is in the form of at least three point-shaped raised portions distributed uniformly in the circumferential direction.
2. Information-carrier according to Claim 1, characterized in that the raised portions (16) are each in the form of a truncated, circular-cylindrical cone.
3. Information carrier according to Claim 1 or 2 , characterized in that there are three to twelve raised portions (16) , preferably roughly six.
4. Information carrier according to Claim 2 or 3 , characterized in that the base of the cone has a diameter of roughly 0.8 mm, while the plane top surface has a diameter of roughly 0.4 mm.
5. Information carrier according to any one of Claims 1-4, characterized in that the height of the raised portions is roughly 0.2 mm.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9801644A SE512109C2 (en) | 1998-05-12 | 1998-05-12 | Disc-shaped, optically readable information carrier |
| SE9801644 | 1998-05-12 | ||
| PCT/SE1999/000796 WO1999062060A1 (en) | 1998-05-12 | 1999-05-11 | Disc-shaped, optically readable information carrier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP1086454A1 true EP1086454A1 (en) | 2001-03-28 |
Family
ID=20411264
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP99927051A Withdrawn EP1086454A1 (en) | 1998-05-12 | 1999-05-11 | Disc-shaped, optically readable information carrier |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP1086454A1 (en) |
| AU (1) | AU4404299A (en) |
| SE (1) | SE512109C2 (en) |
| WO (1) | WO1999062060A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2446438B1 (en) | 2009-06-23 | 2014-03-05 | Thomson Licensing | Data disc, method and system of forming the disc |
| US8623486B2 (en) | 2009-06-23 | 2014-01-07 | Thomson Licensing | Hybrid disc, method and system of forming the disc |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2973155B2 (en) * | 1993-10-29 | 1999-11-08 | 株式会社名機製作所 | Disk substrate and molding die used for molding the disk substrate |
| JPH09180251A (en) * | 1995-12-22 | 1997-07-11 | Pioneer Electron Corp | Disk substrate, metal mold for molding the same, and optical disk |
-
1998
- 1998-05-12 SE SE9801644A patent/SE512109C2/en not_active IP Right Cessation
-
1999
- 1999-05-11 AU AU44042/99A patent/AU4404299A/en not_active Abandoned
- 1999-05-11 EP EP99927051A patent/EP1086454A1/en not_active Withdrawn
- 1999-05-11 WO PCT/SE1999/000796 patent/WO1999062060A1/en not_active Application Discontinuation
Non-Patent Citations (1)
| Title |
|---|
| See references of WO9962060A1 * |
Also Published As
| Publication number | Publication date |
|---|---|
| AU4404299A (en) | 1999-12-13 |
| SE9801644D0 (en) | 1998-05-12 |
| SE9801644L (en) | 1999-11-13 |
| WO1999062060A1 (en) | 1999-12-02 |
| SE512109C2 (en) | 2000-01-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| 17P | Request for examination filed |
Effective date: 20001109 |
|
| AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): CH DE FR GB LI NL SE |
|
| RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: OTB GROUP B.V. |
|
| RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: OTB GROUP B.V. |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
| 18D | Application deemed to be withdrawn |
Effective date: 20041201 |