Product and process for manufacturing an optical disc master

Abstract

The invention discloses a simplified four step process for making an optical disc master or alternatively a WORM disc by first making or obtaining a transparent polymer disc with a tracking groove of desired geometry molded therein, then spin coating an optically active lamina on the grooved side of the disc, then recording data on said polymer disc with groove controlled and tracked laser means by ablating active lamina, forming pits, the shape of which is determined by the groove geometry and finally depositing a conductive and reflective lamina over the pitted active lamina. To change the OD master to an OD WORM, a protective cover is added to the electrically conductive and optically reflective lamina.

What is claimed is: 
     
       1. A process for making an optical disc (OD) master from which an OD WORM may be made comprising the steps of: making a disc substrate having an optical tracking path of a defined geometry delineated on one side of said substrate;   applying a homogeneous, optically active lamina to said path delinated side of said disc substrate;   optically writing data on said active lamina along said path in a series format of variable length bits, the geometry of said bits being substantially controlled and predetermined by the geometry of said path; and   applying a conductive and optically reflective lamina to said active lamina.   
     
     
       2. A process according to claim 1, wherein said disc substrate is a polymer. 
     
     
       3. A process according to claim 1, wherein said tracking path is a spiral commencing at an inner radius and terminating at an outer radius. 
     
     
       4. A process according to claim 1, wherein said tracking path comprises a plurality of concentric circles having a common center at the center of said disc, commencing at an inner radius and terminating at an outer radius. 
     
     
       5. A process according to claim 1, wherein said tracking path is a groove. 
     
     
       6. A process according to claim 1, wherein data bits are optically written along said path by ablation of said active lamina forming a series of variable length pits. 
     
     
       7. A process according to claim 1, wherein said conductive, optically reflective lamina is metallic. 
     
     
       8. A process for making an OD master from which an OD stamper and an OD WORM may be made, comprising the steps of: providing a disc substrate having an optical tracking path of a defined geometry delineated on one side of said substrate;   applying a homogeneous, optically active lamina to said path delineated side of said disc substrate;   optically writing encoded data on said active lamina along said path in a form substantially determined by the physical features of said path itself by laser means positioned on one side of said disc;   optically reading and monitoring accuracy of said encoded data by laser means positioned on the opposite side of said disc while said encoded data is being written; and   applying a conductive and optically reflective lamina to said encoded active lamina.   
     
     
       9. A process for making an OD master from which an OD stamper and an OD WORM may be made, comprising the steps of: making a disc substrate having an optical tracking path of a defined geometry delineated on one side of said substrate;   applying a homogeneous, optically active laminate to said path delineated side of said disc substrate;   optically writing data on said active lamina along said path in a series format of variable length bits, the geometry of said bits being substantially controlled and predetermined by the geometry of said path;   applying a conductive and optically reflective lamina to said active lamina forming an OD master; and   applying a protective coating to said conductive/reflective lamina forming an OD WORM. .Iadd.   
     
     
       10.  An optical disc structure useful for recording an optical disc master from which an optical disc stamper can be made, comprising: a flat, planar substrate having an outer peripheral portion;   a first surface of said substrate having an optical tracking path delineated thereon, said tracking path having characteristics that are essentially identical throughout said tracking path; and   radiation sensitive and ablative lamina means responsive to radiation of a predetermined characteristic deposited on said first surface for optically recording data modulated information in a series of pits within said lamina means in response to radiation of said predetermined characteristic being incident said first surface. .Iaddend. .Iadd.   
     
     
       11.  The disc defined by claim 10 further comprising: said tracking path having a predetermined size and shape including opposed spaced facing side walls and a base between said side walls designed to accommodate creating a pit within said lamina contained within said tracking path using the geometry of said path to assist in controlling the size of said pits; and   whereby, exposure of said tracking path to radiation of said predetermined characteristic creates a pits recorded data that can be used as an optical disc master. .Iaddend. .Iadd.12. The disc of claim 10 wherein said predetermined characteristics consists of an infa red wavelength and said radiation sensitive and ablative lamina means contains an ablative dye that is optically active in response to infa red light; and   whereby, upon exposure of said surface to light of said predetermined characteristics generates heat of sufficient portions to ablate a portion   
     
     
        of said lamina thereby making a recording pit. .Iaddend. .Iadd.13.  The disc of claim 10 wherein said substrate consists of a material that is transparent to radiation of said predetermined characteristics. .Iaddend. .Iadd.14. The disc of claim 10 wherein said substrate is comprised of a material that is opaque to radiation of said predetermined characteristics. .Iaddend. .Iadd.15. A process for making an optical disc (OD) master from which an optical disc stamper can be made comprising the steps of: manufacturing an optical disc substrate having a surface with an optical tracking path of defined geometry delineated on said surface;   applying to said surface, optically active means sensitive to radiation of an predetermined wavelength for forming pits having a size and shape that can be reproduced by an electroforming process;   optically writing data along said path by irradiating said optically active means within said path with radiation having said predetermined wavelength   
     
     
        to form a series pits within said path. .Iaddend. .Iadd.16.  The process of claim 15 further including making an optical disc stamper by applying a conductive lamina to said surface to form a negative of said pitted surface and removing said conductive lamina to form said stamper. .Iaddend..Iadd.17. The process according to claim 15, wherein said disc substrate is transparent and said step of optically writing comprises focusing a laser through said transparent substrate and upon said optically active means within said optical tracking path delineated on said surface. .Iaddend. .Iadd.18. The process according to claim 15 wherein said optically active means consists of a lamina sensitive to infa red light. .Iaddend. .Iadd.19. The process according to claim 15 wherein said optical tracking path is a spiral groove. .Iaddend. .Iadd.20. The process according to claim 15 wherein said optical tracking path is a set 
     
     
        of concentric circles. .Iaddend. .Iadd.21.  A process for making an optical disc (OD) master comprising the steps of: manufacturing a transparent optical disc substrate having a recording surface;   applying to said surface, a homogeneous layer of an optically active lamina;   optically writing data on said surface by focusing laser means through said transparent optical disc substrate from a side opposite said recording   
     
     
        surface. .Iaddend. .Iadd.22.  A process according to claim 21, wherein said manufacturing step further comprises manufacturing an optical disc substrate containing an optical tracking path delineated on said recording surface, said tracking path consisting of radially spaced groove portions defining a land area between said radially spaced grooved portions. .Iaddend. .Iadd.23. A process according to claim 22 wherein said series of data pits are formed within said tracking path. .Iaddend. .Iadd.24. A process according to claim 22 wherein said series of data pits are formed within said land area. .Iaddend. .Iadd.25. A process according to claim 22, wherein said tracking path consists of a V shaped groove. .Iaddend. .Iadd.26. A process according to claim 22 wherein said optical tracking path is a spiral commencing at an inner radius and terminating at an outer radius. .Iaddend. .Iadd.27. A process according to claim 22, wherein said tracking path comprises a plurality of concentric circles having a common center at the center of said disc, commencing at an inner radius and 
     
     
        terminating at an outer radius. .Iaddend. .Iadd.28.  A process according to claim 22, wherein said tracking path consists of a pair of spaced side walls separated by a base. .Iaddend. .Iadd.29. A process to claim 21 further comprising the steps of: forming a conductive lamina upon said recording surface; and   removing said conductive lamina to form an optical disc stamper. .Iaddend. .Iadd.30. A process according to claim 21, wherein said manufacturing step further consists of a using a polymer as said substrate. .Iaddend. .Iadd.31. A process according to claim 21, wherein said manufacturing step further consists of using a glass as said substrate. .Iaddend. .Iadd.32. A process according to claim 31 wherein said data pits form a continuous path containing said series of pits in adjacent radially spaced grooves   
     
     
        portions. .Iaddend. .Iadd.33.  The invention according to claim 32 further comprising reading and monitoring said series of pits by laser means. .Iaddend. .Iadd.34. The process according to claim 33 further comprising making an optical disc stamper by applying a conductive lamina to said recording surface and removing said conductive lamina to make said stamper, therefrom. .Iaddend. .Iadd.35. A process for making an optical disc master from which an optical disc stamper can be made comprising the steps of: providing a disc substrate having an optical tracking path of a defined geometry delineated on one side of said substrate;   applying a homogeneous, optically active lamina to said path delineated side of said disc substrate;   optically writing encoded data on said active lamina along said path by laser means focused on said active lamina to form a series of pits; and   optically reading and monitoring accuracy of said encoded data by laser means focused on said series of pits while said encoded data is being written. .Iaddend. .Iadd.36. A process according to claim 35 further comprising the steps of:   applying a conductive lamina to said encoded active lamina; and   removing said conductive lamina to form an optical an optical disc stamper therefrom. .Iaddend. .Iadd.37. A process according to claim 35 wherein said series of data pits are formed within said tracking path. .Iaddend. .Iadd.38. A process according to claim 35 wherein said series of data pits are formed within a land area defined by said tracking path. .Iaddend. .Iadd.39. A process according to claim 35 wherein said optical disc substrate is transparent. .Iaddend. .Iadd.40. A process according to claim 39, wherein the step of optically writing data pits comprises focusing laser means through said transparent optical disc substrate from a side   
     
     
        opposite said recording surface. .Iaddend. .Iadd.41.  A recorded optical disc product used for making optical disc masters made from the process of: making an optical disc substrate having a recording surface with an optical tracking path of a defined geometry delineated on said recording surface;   applying a homogeneous, optically active lamina to said path delineated surface of said disc substrate; and   optically writing encoded data as a series of pits on said surface along said path, said pits having their geometry substantially controlled by the   
     
     
        dimensions of said path. .Iaddend. .Iadd.42.  A product for optical disc stampers according to claim 41 further comprising the process steps of: applying a conductive lamina over said surface containing said pits such that said conductive lamina conforms to the shape of said surface containing said series of pits and forms a negative pattern thereof; and   removing said conductive lamina containing said negative pattern of said   
     
     
        pitted surface to form said stamper, therefrom. .Iaddend. .Iadd.43.  A recorded disc product used for making optical disc masters made from the process of: making a transparent optical disc substrate having a recording surface on one side;   applying a homogeneous, optically active lamina to said recording; and   optically writing data on said recording surface as a series of pits on said surface, radially spaced from the center of said disc, by focusing laser means through said substrate from an opposite side from that   
     
     
        containing said recording surface. .Iaddend. .Iadd.44.  The product for optical disc masters according to claim 43 further comprising reading and monitoring said series of radially spaced pits by laser means. .Iaddend. .Iadd.45. A product for optical disc stampers according to claim 43 further comprising the process steps of: applying a conductive lamina over said surface containing said pits such that said conductive lamina conforms to the shape of said surface containing said series of pits and forms a negative pattern thereof; and   removing said conductive lamina containing said negative pattern of said pitted surface to form said stamper, therefrom. .Iaddend.