US4627809A
Expired / Lapsed
US
⏱️ 0.0 years remaining
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: 1986-12-09
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Expires: 2004-08-21
Abstract
Abstract A metal mold to be used for injection-molding of a flat plastic disc. The flat, annular mold cavity has a substantially continuously increasing axial thickness away from the injection gate. The gate can be in the center or on the outer periphery of the mold. A split mold type is disclosed wherein at least one of the inner opposed surfaces tapers away from an imaginary flat center plane. Alternatively, a stamper having a tapering thickness can be used in a mold having parallel opposed inner surfaces.
Inventors
- 👤 Norio Okabayashi
- 👤 Yoshio Onizawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:38
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: 11
Claim 1
Independent Claim
102 words
In a metal mold to be used for injection-molding a flat plastic disc having uniform thickness 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 flat and annular injection mold cavity is substantially continuously increased away from a gate at the center of the molding cavity outwardly from the gate to the mold cavity perimeter for injecting the molten resin into the center of the mold and forming a flat resin disc having uniform thickness when molten resin is injection molded in said cavity.
Claim 2
Dependent Claim
102 words
In a metal mold to be used for injection-molding a flat plastic disc having uniform thickness 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 flat and annular injection mold cavity is substantially continuously increased away from a gate at the center of the molding cavity outwardly from the gate to the mold cavity perimeter for injecting the molten resin into the center of the mold and forming a flat resin disc having uniform thickness when molten resin is injection molded in said cavity.
Claim 3
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 4
Dependent Claim
34 words
The metal mold as defined in any one of the claims 1 or 2, wherein said molding cavity is defined by a first split mold and a second split mold having axially opposed surfaces.
Claim 5
Dependent Claim
47 words
The metal mold as defined in claim 3, wherein the axial thickness of said molding cavity is varied by tapering at least one of the axially opposed surfaces of said first and second split molds relative to an imaginary central plane of said flat annular molding cavity.
Claim 6
Dependent Claim
38 words
The metal mold as defined in any one of claims 1 or 2, further comprising a stamper disposed on at least one of the axially opposed surfaces formed by first and second split molds forming said molding cavity.
Claim 7
Dependent Claim
52 words
The metal mold as defined in claim 5, wherein said inner surfaces of said first and second split molds in said molding cavity are parallel to an imaginary central plane, and a thickness of said stamper is continuously decreased radially away from a point near the injection gate of said molding cavity.
Claim 8
Dependent Claim
76 words
The metal mold as defined in claim 5, wherein a thickness of said stamper is substantially uniform from a point near a central portion to a radially outer peripheral portion, and a distance between at least one of said inner surfaces of said first and second split mold cavity and an 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 9
Dependent Claim
80 words
In a stamper to be disposed in a metal mold for injection-molding a flat plastic disc having uniform thickness for a high-density information recording carrier by injecting molten resin into a flat annular injection molding cavity, the improvement characterized in that a thickness of said stamper is continuously decreased radially outwardly away from an injection gate at the center of said mold cavity to the mold cavity perimeter for the molten resin for injecting molding flat disc having uniform thickness.
Claim 10
Dependent Claim
80 words
In a stamper to be disposed in a metal mold for injection-molding a flat plastic disc having uniform thickness for a high-density information recording carrier by injecting molten resin into a flat annular injection molding cavity, the improvement characterized in that a thickness of said stamper is continuously decreased radially outwardly away from an injection gate at the center of said mold cavity to the mold cavity perimeter for the molten resin for injecting molding flat disc having uniform thickness.
Claim 11
Dependent Claim
25 words
The stamper as defined in claim 8, wherein said stamper has a submicron order unevenness for signals on its surface opposed to said molding cavity.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-12-08 | 1990-06-09 | 1990-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-08 | 1994-06-09 | 1994-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-08 | 1998-06-09 | 1998-12-09 | $7700.00 | Window Closed / Lapsed |