JPS6360450B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an optical reflective layer on a substrate having a recording surface carrying information on the upper surface, and forms a protective layer to protect this reflective layer by printing, and at the same time forms a protective layer that protects the reflective layer. Concerning an optical recording medium on which information is printed.

Bits or bumps formed on a transparent substrate are used as information sources, the surfaces of these pits or bumps are covered with a reflective film, and radiation is applied from the large surface of the substrate.
2. Description of the Related Art A reproducing device is known in which information is electrically read from reflected light using an optical-to-electrical converter. In the recording medium used in this reproducing device, a protective layer is formed to cover the entire surface of the reflective film in order to protect the reflective film. This protective layer is made of, for example, an ultraviolet curing resin, which is coated onto the upper surface of the reflective layer in an appropriate planar shape, and then cured by irradiation with ultraviolet rays.

A so-called label, generally paper, indicating the information on the medium is pasted onto the cured protective layer at the center of the medium using an adhesive. However, the medium obtained through such a process has the following disadvantages. For example, there is a risk that the paper label may be misaligned when it is attached, the attachment may be insufficiently integrated, or the contents of the medium may be inconsistent with the items written on the label. In particular, since adhesive is used, if the adhesive is applied unevenly, the weight balance of the medium will be uneven, and when the medium containing minute information is attached to a playback device that is read out while rotating at high speed, the surface will run out. This may cause problems with proper playback. Furthermore, the process of forming a protective film for the reflective layer and the process of attaching a label are different, resulting in an increase in the number of manufacturing steps.

The present invention provides an optical recording medium in which the protective film of the reflective layer and the so-called label portion are simultaneously formed by printing technology, thereby eliminating the above-mentioned disadvantages.

An embodiment of the optical recording medium according to the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a base of a disc-shaped recording medium called a replica, which is made of a light-transmitting resin, such as acrylic resin. The upper surface 1a of this base 1
A recording surface 2 is formed on which sound or video, or sound and video, or other information is formed in a concave and convex manner. The uneven recording portion is formed concentrically or spirally on the base 1 so that the recessed portions are discontinuous. The process of manufacturing the base 1 from a master disc is, as is generally known, by electroforming the recording surface of the master disc to obtain a mother disc, electroforming the recording surface of this mother disc, and then forming the mother disc. The electroformed layer is peeled off from the disk to obtain a stamper. A reinforcing layer is formed on the back surface of the stamper.The thus obtained stamper is placed in a mold, and the above-mentioned medium 1 is molded by injection molding or compression molding. A hole 3 for inserting a spindle is formed in the center of the base 1, and the center portion of the base 1 is a flat portion 4 that is continuous with the recording surface 2 and is a non-recorded portion.

On the upper surface 1a of the base 1 configured as above,
A radiation reflective layer 5 is provided as shown in FIG. This reflective layer is made of aluminum, for example, and can be applied to the upper surface 1a, for example by sputtering or vacuum deposition. In addition,
The reflective layer 5 covers not only the recording surface 2 but also the central plane part 4.
It is also uniformly applied. The reflective layer 5 deposited in this manner is extremely thin and easily scratched and peeled off. In order to prevent such inconvenience, a protective layer is generally formed on the upper surface of the reflective layer 5. The present invention is characterized in that such a protective layer is formed on the reflective layer using a printing technique, and at the same time, an indication of what the information on the substrate relates to is formed on the flat surface via the reflective layer. do. The third example of printing technology is tampo printing.
The process will be explained below in the figure.

7 shown in FIG. 3 is used for pad printing. It is a plan view of the so-called plate, and its central part 8
A display 8 indicating what the information on the base 1 relates to is carved in a concave shape by etching or the like. For example, if the recording medium is for music, this display is composed of a program section 8a, a performer 8b, front and back marks 8c, and the like. At the same time, a concave portion 9 is etched slightly deeper than the display 8 on the outer periphery of the central portion. The cross section of these display and recessed parts is shown in FIG. 4, and the display part corresponds to the flat part 4 of the base 1, and the recessed part 9 corresponds to the recording part 2 in which information is recorded. Next version 7
Each recess is filled with ink 10a, 10b as shown in FIG. Thereafter, a pad 11 made of silicone rubber or the like is pressed from above the plate 7, and the ink 10a, 10b is applied to the surface of the pad 11 as shown in FIG.
to be adsorbed. Next, the pad 11 containing the inks 10a and 10b is pressed onto the base 1 on which the reflective layer is formed as shown in FIG. 7 after aligning the center position or the circumference. This pressing causes the inks 10a and 10b to be transferred onto the substrate 1. The ink thus transferred is solidified on the substrate 1 as shown in FIG. 8, and the ink 10b filling the recesses 9 of the plate 7 becomes the protective layer 13 of the reflective layer 5. The ink 10a also serves as an indication 14 of what the information relates to. This display 14 corresponds to a so-called label portion. FIG. 8 shows the completed recording medium. For reproduction, radiation such as a laser beam is irradiated from below the base 1,
Information on the medium can be converted into an electrical signal by using the light reflected from the reflective layer 5 by an optical-to-electrical converter.
As shown in FIG. 9, although the reflective layer 5 is exposed in the display 14 portion, the reflective layer on the important information recording section is completely covered with the protective layer 13, so there is no problem with reproduction. In the above example, printing was performed directly on the label-equivalent area, but a thin protective film was formed in advance on the flat surface 4 of the label-equivalent area by pad printing, etc., and then the protective layer 13 and display 14 were formed as shown in FIG. may be printed at the same time by pad printing. Furthermore, since pad printing allows multicolor printing, it is possible to display the display section (label section) in multiple colors. Further, the tampon for tampo printing may be in the form of a roll. Furthermore, this printing may be screen printing, gravure printing, etc. instead of pad printing.

As described above, according to the present invention, the protective layer 13 and the display 14 can be formed simultaneously by printing, which has the advantage of simplifying the process. Further, according to the present invention, since the display is provided by printing, there is no risk that the display or label may be pasted incorrectly, misaligned, or insufficiently pasted, unlike in the past. In addition, according to the present invention, since the display is provided by printing, there is no need to use adhesive. Therefore, uneven application of the adhesive causes uneven weight balance of the medium, causing surface wobbling during playback. There are no other inconveniences.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views for explaining the optical recording medium, Figure 3 is a top view showing an example of a pad printing plate, Figure 4 is a cross-sectional view taken along the line shown in Figure 3, and Figure 5. , FIG. 6 and FIG. 7 are process diagrams showing an example of using pad printing in the present invention, FIG. 8 is a cross-sectional view showing an example of the optical recording medium of the present invention, and FIG. 9 is a process diagram showing an example of using pad printing in the present invention. FIG. 2 is a partially enlarged cross-sectional view. 1 is the base of the recording medium, 2 is the recording surface, 4 is the flat surface, 5 is the reflective layer, 10a and 10b are ink, 13 is the protective layer, and 14 is the display.

Claims (1)

[Claims] 1 Forming a recording surface on which information is discontinuously recorded on the upper surface of a transparent substrate and a flat part continuous with this recording surface, so that the recording surface can be optically read on the upper surface of the substrate. In an optical recording medium provided with a radiation reflective layer, a protective layer is formed by printing ink on the upper surface of the radiation reflective layer, and at the same time, information related to the information is displayed on the upper surface corresponding to the flat part of the substrate. An optical recording medium characterized by being printed.