Optical information recording medium and method for producing sa

Details Optical information recording medium and method for producing sa Optical information recording medium and method for producing sa

1996-09-12

1998-11-24

Krynski, William

Stock material or miscellaneous articles

Circular sheet or circular blank

428 642, 428 644, 428 647, 428 648, 428913, 369288, B32B 300

Patent

active

058403957

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

This invention relates to an information recording medium for optically reading out information signals by laser light. More particularly, it relates to an optical information recording medium which is colored for enabling the sort or application thereof to be instantly determined on visual check.


BACKGROUND ART

Among so-called compact discs, those discs having audio signals digitally recorded thereon have so far been predominant. Recently, so-called CD-ROMs having computer programs or data recorded thereon, have been developed, thus increasing the number of sorts and the field of application of the compact discs.
With increase in the number of sorts and the usage of the compact discs, demand has been raised for providing the CD with some discrimination means. For example, if different colors are afforded to the CD according to the sorts and the usage, it may be expected that the user is able to discriminate the CD instantly.
For affording color to the CD, the simplest and easiest method is to color a plastic substrate itself with coloring matter.
Among the methods for coloring plastics, there is known a method of preparing a coloring compound and subsequently producing a colored molded article by a molding device. There are also known other methods, such as a method consisting in mixing powdered coloring agents termed a dry color with an non-colored resin (dry blend method) and in dispersing the resulting mixture by a molding device for preparing a colored molded article, a method consisting in diluting a coloring agent, obtained on dispersing high-density dyestuff or pigments, termed a master batch, with a non-colored resin, and employing the resulting diluted coloring agents for coloring, and a method, termed a liquid coloring method, consisting in dispersing a dyestuff and the pigment in a liquid vehicle and supplying the resulting paste-like coloring agent in metered quantities using a pump.
In general, the dyestuff is readily dissolved in plastics and superior in dispersibility. Thus a satisfactory colored molded article may be obtained by the dry blend method with the use of commercial dyestuffs.
However, since not only the appearance but also a variety of optical properties are required of CDs, simple application of the above methods is not sufficient to give satisfactory results.
It is therefore an object of the present invention to provide an optical information recording medium which is colored to enable the sorts and the usage etc. to be discriminated instantly and which has superior optical properties. It is also an object of the present invention to provide a method for producing such optical information recording medium.


DISCLOSURE OF THE INVENTION

For accomplishing the above objects, the present inventors have long conducted a variety of investigations, and thus arrived at a conclusion that the particle size of the coloring matter mixed into the plastic substrate significantly influences the error rate at the time of reproducing data from the optical information recording medium.
The present invention has been completed based on this information. That is, the present invention provides an optical information recording medium including a plastic substrate colored by admixture of the coloring matter and a signal recording portion from which information signals are optically read out, wherein the particles of the coloring matter admixed into the plastic substrate are not more than 50 .mu.m in size.
The present invention also provides a method for producing an optical information recording medium including the steps of dispersing the coloring matter in a dispersion medium to produce the liquid coloring matter, passing the liquid coloring matter through a filter for removing coarse particles therefrom for preparing the liquid coloring matter with the maximum particle size of the pigments being not more than 50 .mu.m, and supplying the liquid coloring matter into a resin injection hopper of an injection molding device for injection molding a plastic substrate.
Among basic p

REFERENCES:
patent: 5190800 (1993-03-01), Takashi et al.

Affiliated with

Also associated with

Rating

Optical information recording medium and method for producing sa does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Optical information recording medium and method for producing sa, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical information recording medium and method for producing sa will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1699857