 Range Doppler self-referencing imaging system |
| The need in the art for a long range imaging system capable of operating at visible wavelengths is ... |
|
| Christmas tree ornament with photo display |
| OF THE PREFERRED EMBODIMENT Before explaining in detail the present invention, it is to be ... |
|
| Optical fiber |
| A primary object of the present invention is to provide an optical fiber having a wide transmission ... |
|
| Waveguide and method of manufacturing same |
| The present invention is directed to a dielectric waveguide in which cross couplings between ... |
|
| Polarization-retaining single-mode optical waveguide |
| It is therefore an object of the present invention to provide an improved polarization stabilized ... |
|
| Chromatically invariant multilayer dielectric thin film coating |
| The inventive optical filter is a short-wave-pass (SWP) filter deposited upon a substrate where the ... |
|
| Abrasive filaments and production process thereof |
| An object of this invention is to provide abrasive filaments made of a synthetic resin, which ... |
|
| Wholly aromatic polyester |
| A wholly aromatic polyester according to the present invention is the one consisting essentially of ... |
|
| Self reinforced composite of thermotropic liquid crystal polymers |
| What is claimed is: 1. A blend of thermotropic liquid crystal polymers, said liquid crystal ... |
|
| Polarizing beam splitter using dielectric multilayers |
| What is claimed is: 1. An analyzer for determining the polarization state of a light beam ... |
|
|
Disc medium substrate and disc device
| Details |
Inventors: Oyanagi, Eiki; Sasa, Takeshi; Imai, Yasuyuki; Takino, Hiroshi; Kohara, Teiji; Oshima, Masayoshi;
Assignee: Sony Corporation (Tokyo, JP); Nippon Zeon Co., Ltd. (Tokyo, JP)
Primary Examiner: Evans; Elizabeth
Assistant Examiner:
Attorney, Agent or Firm: Hill & Simpson
A molded thermoplastic resin disc substrate specially adapted for use with floating head type recording/reproduction apparatus is provided. The molded disc substrate has surface smoothness characteristics which are the same or better than are provided with mirror polished aluminum discs. The molded disc substrates include a floating head scanning surface wherein the maximum projection height or maximum surface irregularity is less than about 50 nm to reduce or eliminate damage to either the disc or floating head caused by unwanted collisions between them. In a preferred embodiment, the molded disc substrates are molded from a thermoplastic resin composition containing 10000 particles/gram or less of particles having a particle diameter of 0.5 .mu.m or more. In a preferred embodiment, control of particle size and content is achieved by subjecting the resin molding composition to a sequence of filtering steps using filters of decreasing mesh size. |
|
DETAILED DESCRIPTION We claim: 1.
A substrate for disc medium for use in a recording and/or reproduction system employing a floating head, comprising: a molded thermoplastic disc medium substrate including a floating head scanning surface defined thereon having a surface smoothness such that projections having height of 50 nm or more are not formed at least on the floating head scanning surface of the disc medium substrate where the floating head scans.
2.
A substrate for disc medium as set forth in claim 1, wherein the disc medium substrate is molded by injection-molding resin.
3.
A substrate for disc medium as set forth in claim 2, wherein the resin is thermoplastic norbornene resin.
4.
A substrate for disc medium as set forth in claims 3, wherein uneven portions corresponding to recording tracks are provided at least on one principal surface.
5.
A method of manufacturing a substrate for disc medium wherein, in molding resin so as to take shape of substrate for disc medium, control is conducted such that the number of particles of foreign matter having particle diameter of 0.
5 .
mu.
m or more within molded body is 10000/g or less to carry out molding.
6.
A method of manufacturing a substrate for disc medium as set forth in claim 5, wherein the molding is injection molding.
7.
A method of manufacturing a substrate for disc medium as set forth in claim 6, wherein the resin is thermoplastic norbornene resin.
8.
A substrate for disc medium of resin used as a disc medium adapted so that recording and/or reproduction are carried out by a floating head, wherein the disc medium substrate is molded under a condition such that the number of particles of foreign matter having particle diameter of 0.
5 .
mu.
m or more is 10000/g or less.
9.
A substrate for disc medium as set forth in claim 8, wherein the disc medium substrate is molded by injection-molding resin.
10.
A substrate for disc medium as set forth in claim 9, wherein the resin is thermoplastic norbornene resin.
11.
A disc apparatus provided with a disc using a substrate for disc medium of resin adapted so that recording and/or reproduction are carried out by a floating head and projection having height of 50 nm or more is not formed on the surface of the disc medium where the magnetic head scans
|
| Related patents |
|
|
Snow plowable pavement marker
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 1. A snow plowable pavement marker comprising: a body ...
|
|
|
Rotary power trowel
It is accordingly an object of the present invention to provide a rotary power trowel having a safety clutch mechanism requiring no manual engagement and capable of ...
|
|
|
Drive mechanism
I claim: 1. Apparatus (10), comprising: a frame (18) including a yoke (16); a compacting drum (14) having an axis of rotation (28) and being rotatably mounted on said ...
|
|
|
Soliton laser
Soliton Effects Before discussing in detail my invention, it will be instructive to consider first the nature of pulse compression and solitons in optical fibers. Pulse ...
|
|
|
Short optical pulse generator having a looped directional coupler external cavity
With reference to FIG. 1, laser diode 101 is a typical, commonly available, laser diode chip having at one end a highly reflective coating or layer 102, and at its ...
|
|
|
Chemical process yielding stimulated emission of visible radiation via fast near resonant energy transfer
OF THE INVENTION The present invention employs the concept demonstrated by the superfluorescence associated with an atomic transition of a Group IIIA metal or semimetal ...
|
|
|
In-line fiber optic memory
What is claimed is: 1. A fiber optic recirculating memory, comprising: a length of optical fiber, for receiving an optical signal pulse, said fiber forming a loop; an ...
|
|
|
Optical signal network with node by-pass switching capability
We claim: 1. An optical signal network having plural optical signal input/output nodes interconnected by optical fibres and having at least one such node which includes: ...
|
|
|
Laminates
What we claim is: 1. A laminated panel which comprises a core of rigid isocyanurate based foam sandwiched between two facing sheets, characterized in that there is ...
|
|
|
Anamorphic attachment for purpose of filming and reproduction to be used together with a basic lens
FIG. 1a represents the most simple embodiment possibility of the attachment of this invention and, at the same time, the basic arrangement and design. In FIG. 1a the ...
|
|
|
Optical Systems 
