Patent EP0137246A2 successfully refreshed from Google Patents.
EP0137246A2
Expired / Lapsed
EP
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Metal mold and stamper for injection molding of a plastic disc for a high-density information recording carrier
Assignee: Daicel Corp
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Filing: 1984-08-21
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Granted: —
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Expires: 2004-08-21
Abstract
Abstract The present invention relates to an improvement in a molding method of a disc, particularly a plastic disc for a high-density information recording carrier such as a video disc, an optical disc and the like, and more particularly an improved metal mold and a stamper to be used for an injection molding of the plastic disc.
Inventors
- 👤 Norio Okabayashi
- 👤 Yoshio Onizawa
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 16:33
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/26; B29C45/263; B29C45/2632; B29C2045/2661; Y; Y10; Y10S; Y10S425/00; Y10S425/81
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
58 words
In a metal mold to be used tor infection-molding a plastic disc for a high-density information recording carrier by injecting molten resin into a flat and annular mold cavity, the improvement characterized in that an axial thickness of the mold cavity is substantially continuously increased with leaving a gate of the molding cavity for injecting the molten resin.
Claim 2
Dependent Claim
58 words
In a metal mold to be used tor infection-molding a plastic disc for a high-density information recording carrier by injecting molten resin into a flat and annular mold cavity, the improvement characterized in that an axial thickness of the mold cavity is substantially continuously increased with leaving a gate of the molding cavity for injecting the molten resin.
Claim 3
Dependent Claim
28 words
The metal mold as defined in claim 1, wherein said injection gate of the molten resin is provided in the vicinity of the center of the molding cavity.
Claim 4
Dependent Claim
30 words
The metal mold as defined in claim 1, wherein there is provided a flash gate in the vicinity of the outer periphery in the radial direction of the mold cavity.
Claim 5
Dependent Claim
29 words
The metal mold as defined in any one of claims 1 to 3, wherein said molding cavlty is defined by a first split mold and a second split mold.
Claim 6
Dependent Claim
45 words
The metal mold as defined in claim 4, wherein the axial thickness of said molding cavity is varied by tapering either or both of axially opposed surfacesaf said first and second split mold relative to an imaginary central plane of said flat annular molding cavity.
Claim 7
Dependent Claim
37 words
The metal mold as defined in any one of claims 1 to 3, and further comprising a stamper disposed on either or both of inner surfaces formed by said first and second.split molds in said molding cavity.
Claim 8
Dependent Claim
52 words
The metal mold as defined in claim 6, wherein said inner surfaces of said first and second split mold in said molding cavity are parallel to the imaginary central plane, and a thickness of said stamper is continuously decreased with radially leaving a point near the injection gate of said molding cavity.
Claim 9
Dependent Claim
78 words
The metal mold as defined in.claim 6, wherein the thickness of said stamper is substantially uniform from a point near a central portion to an radially outer peripheral portion, and a distance between at least one of said inner surfaces of said first and second split mold in said mold cavity and the imaginary central plane of said flat molding cavity is continuously increased from a point near the radially central portion to the radially outer peripheral portion.
Claim 10
Dependent Claim
54 words
In a stamper to be disposed in a metal mold for injection-molding a plastic disc for a high-density information recording carrier by injecting molten resin into a flat annular molding cavity, the improvement characterized in that a thickness of said stamper is continuously decreased with radially leaving an injection gate for the molten resin.
Claim 11
Dependent Claim
54 words
In a stamper to be disposed in a metal mold for injection-molding a plastic disc for a high-density information recording carrier by injecting molten resin into a flat annular molding cavity, the improvement characterized in that a thickness of said stamper is continuously decreased with radially leaving an injection gate for the molten resin.
Claim 12
Dependent Claim
25 words
The stamper as defined in claim 9, wherein said stamper has a submicron order unevenness for signals on its surface opposed to said molding cavity.
References Cited (Backward Citations)
No citation records indexed.
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