JPH01224949A - Manufacture of optical recording medium - Google Patents

Abstract

PURPOSE:To highly accurately forming a recording layer by etching the exposure part of a film for projected line, forming a track groove on a substrate, providing a recording layer forming film in the track groove and further, removing a protective resin layer and the recording layer forming film formed on the layer by means of the same process. CONSTITUTION:A film 11 for projected line consisting of SiO2 is formed on a circular board 10, a photo-resist layer 12 is formed on the surface, excimer laser light is projected on a photomask in a condition to be stuck on the resist layer 12, the resist layer 12 of the exposure part is deteriorated, dissolved and removed by a developer, and a track pattern is formed. Next, the exposure surface of the film 11 for the projected line is etched with the resist layer 12 as mask, a projected line 13 is formed in a track shape to prepare a track groove 3, a TeOX thin layer 14 is evenly formed on the projected line 13 forming surface, a residual resist layer 12 on the projected line 13 surface is dissolved by an organic solvent, the resist layer 12 and the TeOX thin layer 14 on the resist layer 12 are removed, and the TeOX thin layer 14 in the track groove 13 is left to be a recording layer 4. Thus, the recording layer can be highly accurately and surely formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to optical discs and optical discs that optically record and reproduce information, or record, reproduce, and erase information by irradiating focused light from gas lasers, semiconductor lasers, etc. The present invention relates to optical recording media such as magnetic disks, and particularly relates to a method of manufacturing an optical recording medium in which a recording layer is selectively provided only in the track grooves of a substrate.

[Prior Art 1] A conventional optical recording medium has a recording layer on one side as an example. As shown in FIGS. 3 and 4, a pregroup for focusing and tracking servo is used. -aroove) (a); a recording layer (C) provided on the entire surface of this substrate (b); and a protective layer (C) provided on the entire surface of this recording layer (C).
The main part of the optical recording medium (e) is composed of d), and information to be recorded on the optical recording medium (e) is input using a light source such as a semiconductor laser focused by a condensing lens (f) as shown in FIG. A focused recording light (Q) is irradiated to a predetermined region of the recording layer (C), and a phase change of the recording layer (C) is caused in the irradiated region;
Magnetization reversal or deformation is caused to create a recording dot (h) that has a different reflectance or Kerr rotation angle from the non-irradiated area.
(see FIG. 4). In this case, in order to reliably irradiate the focused light (Q) from the light source to a predetermined portion of the recording layer (C), focusing and tracking servo control are performed using the pre-group (a>), and the recording dots are (h) Width dimension (B)
As shown in Fig. 6, the intensity change in the focused recording light spot (+) is set to about the half-width (Ω2) at which the intensity change is the steepest, and recording dots (h) of approximately the same size are stabilized. adjusted to form.

On the other hand, when reproducing the recorded information, FIGS.
As shown in the figure, the focused light for reproduction (q) is transferred to the optical recording medium (e).
The reflected light is input to a light-receiving element (j) such as a photodiode for reproduction. in this case,
The light from the entire focused light spot for reproduction is used for reproduction, and as shown in Figure 6, typically the light in the 1/e2 full width Ωe) region of the focused light spot for reproduction (+) is used for the reproduction signal. It is thought that this contributes. In addition, (p) in FIG. 3 shows the optical head for reproduction, and the semiconductor laser (pl)
and a condensing lens (p2) that focuses this laser beam onto the surface of the optical recording medium (e), a beam splitter (p3) and a half mirror (p4) that polarizes the reflected beam from the optical recording medium (e). , a servo signal detector (p5), and a reproduced signal receiver (p6).

By the way, since the conventional optical recording medium (e) is provided with the recording FJ (c) on the entire surface of the substrate (b) as described above, it has various drawbacks as shown below.

First, the track pitch (TP
) can be set narrowly to the point where signals on adjacent tracks are not mixed into the reproduced signal, and its minimum value (TP, .

) is calculated from Figure 9(d) by considering only the crosstalk with adjacent tracks during playback.
/2.

However, (B) shows the width dimension of the recording dot (h), and (Ωe) shows the 1/e2 full width at the focused light spot for reproduction (i).

On the other hand, conventionally, the width dimension (B) of the recording dot (h) is the half width (Ω) of the recording focused light spot (i) as described above.
2), the only way to improve the track density on the optical recording medium is to set the spot diameter (Ωe, Ω2) of the focused light (Q) small, and Regarding the diameter (Ω2), if it is set too small, a slight dimensional error on the substrate surface will cause a recording malfunction, so there is a restriction that it cannot be set below a certain level, so there is a drawback that there is a certain limit to the above-mentioned density improvement. .

Furthermore, since the recording material constituting the recording layer (C) usually has thermal conductivity, as the scanning of the recording spot progresses, heat tends to leak to the periphery due to the influence of this thermal conductivity, and the recording width decreases. The recording dot (h) increases as shown in FIG.
) sometimes took the form of a so-called "teardrop-shaped dot."

For this reason, as shown by α in FIG. 11, the reproduced signal is likely to be distorted, causing large jitter, and
There was a drawback that the /N ratio decreased.

Furthermore, the diameter (Ωe) of the focused light spot for reproduction (+) is larger than the diameter (B) of the recording dot (h) as described above, and moreover, for the optical recording medium (e), its substrate (b) ) Since the recording layer (C) is provided on the entire surface, there is a drawback that the noise of the optical recording medium (e) greatly affects the reproduced signal during reproduction. That is, the 11th
As shown in the figure, on the surface of the recording layer (C) of the optical recording medium (e), there are many noise generation sites (nl) to (nl) with different reflectances due to defects in the medium itself, crystal grains, etc. In addition, there are also noise generation areas (n2) to (n2) at the periphery of the recording dot (11) caused by the unevenness of the dot shape, and these noises are mixed into the reproduced signal. This was a major obstacle to improving the N ratio (1st
See the C/N ratio indicated by α in Figure 9. However, C indicates the carrier signal level, and N indicates the noise signal level.)

Furthermore, in optical recording media for recording, playback, and erasing, when erasing recorded information, the sensitivity of the recording layer decreases due to aging, fluctuations in the output of the focused light for erasing, and tracking deviation. As shown in Figure 12, there is a drawback that the recorded information cannot be completely erased. On the other hand, in order to eliminate this drawback, the spot diameter (Ω) of the focused light for erasing is changed from the spot diameter (Ω2) of the focused light for recording. If it is set to a large value, there is a drawback that the track density decreases.

In addition, in a conventional optical recording medium, recording [1(C)] is formed on the entire surface of the substrate (b), so recording 1(c) is formed on the entire surface of the substrate (b).
Due to the stress during formation and the difference in expansion coefficient between the substrate (b) and the recording layer (C), two-dimensional internal stress (St) is likely to be applied to the recording layer (C) as shown in Figure 13, and the stress increases over time. However, there was a drawback that the recording performance was easily deteriorated.

Therefore, as a result of intensive research to solve the above-mentioned drawbacks, the applicant has developed a product that has high track density, C/N ratio, etc., low playback noise and servo signal noise, and has long-term recording performance. We have already proposed an optical recording medium that does not deteriorate.

That is, as shown in FIG. 14, this optical recording medium (e'') consists of a substrate (bo), track grooves (ao) provided at a plurality of intervals on the negative side of the substrate (bo), A recording layer (Co) provided in the track groove (ao) and a protective layer (Co) provided on the recording layer (Co) side as necessary.
(d') constitutes the main part thereof, and the width dimension of the track groove (ao) is set to be approximately equal to or less than the half width of the focused recording light spot.

Then, as shown in FIGS. 14 and 15, while performing focusing and tracking control using the track groove (AO), a predetermined portion of the recording layer (Co) is irradiated with focused recording light, and its diameter is A recording dot (ho) having a half width (Ω2) of a focused recording light spot is formed, and the recording dot (ho) is read by a focused reproduction light to obtain a reproduction signal.

In the optical recording medium (eo) configured in this way,
As shown in FIGS. 15(b) and (d), the width dimension (B) of the recording dot (ho) is the same as the width dimension (T) of the track groove (ao), and this width dimension ? f(T)
is set to be less than the half width (Ω2) of the focused recording light spot, so the minimum value of the track pitch (D P゛, ) of this optical recording medium (eo) and the track pitch of the conventional optical recording medium The relationship with the minimum value (TP ・ ) is 11n (TP', ) < (TP
, )man
This has the advantage that the track pitch (TP>) can be set small and the track density can be improved.

Moreover, in this optical recording medium (e'), its recording layer (
Since the recording dots (Co) are formed in the shape of the track grooves (ao), it is possible to form recording dots (ho) in a shape close to a rectangle, unlike the conventional "teardrop shape", as shown in FIG. can.

Therefore, as shown by β in FIG. 17, the reproduced signal waveform during reproduction is not distorted, which has the advantage of improving both the C/N ratio and jitter.

Furthermore, since this optical recording medium (0゛) does not have a recording layer (Co) in any part other than the track 1l(a'), the medium noise is reduced and the recording dots (ho
) is regulated by the track groove (ao) and does not vary, so the reflectance unevenness and magnetic domain distribution unevenness at the boundaries of the recording dots (ho) are reduced, and the C/
It has the advantage of improving the N ratio. In other words, when the noise of a light source such as a semiconductor laser is sufficiently suppressed, the reproduction signal noise during reproduction is generally caused by medium noise caused by defects in the optical recording medium, crystal grains, etc., and by unevenness in the shape of recording dots. Recording noise becomes dominant. Since this optical recording medium (eo) does not have a recording layer (Co) in areas other than the track grooves (ao), the above-mentioned medium noise is reduced, and as shown in FIG.
Both side edges of the track groove (a) are formed with high precision.
o), recording dots (ho) are less likely to have uneven shapes, and recording noise is also reduced. Therefore, since the above-mentioned noise signal is less likely to be mixed into the reproduced signal, there is an advantage that the C/N ratio is significantly improved as shown by β in FIG. 19.

Furthermore, in conventional optical recording media for recording, reproducing, and erasing, recorded information cannot be completely lost due to factors such as decreased sensitivity of the recording layer due to deterioration over time, fluctuations in the output of the focused light for erasing, and tracking deviation. Although there is a drawback that erasing cannot be performed, it has the advantage that no unerased areas occur because there is no recording layer (Co) in the area where unerased areas occur, as shown in FIG.

In addition, since the recording layer (Co) in the track groove (ao) is continuous only in the length direction and not in the width direction, internal stress of the recording layer (C') as shown in FIG. (St) becomes -dimensional and is significantly relaxed, and if the recording material is a phase change type, the atomic migration process of crystallization and amorphization in the recording erasing process also proceeds one-dimensionally, so the recording layer Compositional fluctuations in (Co) and in-plane composition variations are less likely to occur, and
) and the stability of the recorded bits, it has the advantage of improved repeatability and stable recording performance over a long period of time.
It has various advantages such as speeding up each process and enabling high-speed recording and erasing.

[Problems to be Solved by the Invention] By the way, in manufacturing this improved optical recording medium, unlike conventional optical recording media in which a recording layer is provided on the entire surface of the substrate, a recording layer is formed only on the track grooves provided on the substrate. It was necessary to selectively form the recording layer.

However, since the width dimension of the track groove is set to an extremely small value, the formation operation of the recording layer is difficult, and there is a problem that it is difficult to manufacture the recording layer accurately and efficiently.

Moreover, if the recording layer is accidentally formed in a part other than the track groove, the recording layer in this part will be affected by the medium noise.
Since this causes recording noise, there is a problem in that the C/N ratio decreases, similar to conventional optical recording media.

[Means for Solving the Problems] The present invention has been made in view of the above-mentioned problems, and its object is to provide a method for manufacturing an optical recording medium with good productivity and good recording accuracy. It is about providing.

That is, the present invention provides an optical recording medium that optically records, reproduces, or erases information by irradiating it with focused light, which comprises a substrate and track grooves formed at a plurality of intervals on at least one surface of the substrate. and a recording layer formed in this track groove, a film forming step of forming a 5-layer film on a substrate, this film on the above-mentioned white butterfly film. a resin layer forming step of forming a protective resin layer for protecting the above-mentioned section 5 with the film partially exposed; and etching the exposed portion of the above-mentioned section 5 coating to form a convex groove for forming a track groove. a recording film forming step of forming a recording layer forming film on the track groove formed by the projection and the protective resin layer, and a recording layer formed on the protective resin layer and the upper surface thereof. and a recording layer forming step of removing the formation film to expose the convexity, and leaving the recording layer formation film in the track groove formed by the convexity as a recording layer. This is a characteristic feature.

In such technical means, the substrate in the film forming step is desirably a light-transmitting material since focused light is irradiated from the substrate side, such as glass, polycarbonate, polyacrylonitrile, polymethyl methacrylate, Examples include epoxy resin and polypentene. Further, the substrate may be made of a single light-transmitting material, or the substrate may be formed by laminating a plurality of the light-transmitting materials. Furthermore, although the shape of the substrate is usually circular, it is preferably rectangular in the case of a card-type optical recording medium. In addition, in optical recording media in which recording/reproduction or recording/reproduction/erasing is performed by irradiating focused light from the opposite side of the substrate, the substrate is naturally made of a light-opaque material other than the above-mentioned light-transmitting material. may be configured.

In addition, the film forming material for the protrusions in this film forming process must have appropriate mechanical strength and be etched in the following protrusion forming process, such as 5102, Si N, ZnS, ZrO
Inorganic materials such as □ are suitable, but resin materials may also be used as long as the etching rate is different from that of the substrate material. Further, as for the formation method, a method suitable for the material used can be applied, and for example, a formation method that can form a uniform film on the substrate, such as a vapor deposition method, a sputtering method, a spin code method, etc., can be used.

Furthermore, the thickness of the convex film is the depth of the track groove, and usually the thickness is 300 to 3.
000 angstroms are set in the garden.

Next, in the resin layer forming step, a protective resin layer is formed in a pattern on the 5-layer coating to protect the convex film under the protective resin layer from etching in the following convex formation step. As the material for forming the protective resin layer suitable for this process, it is preferable to use a material that can be easily removed by the following recording layer forming process. Specifically, it is made of a mixture of novolac resin and O-quinonediazide. Examples include photoresist materials. Further, as a method of forming a protective resin layer with the above-mentioned convex layer film partially exposed, for example, a photoresist material is coated on the 5-layer layer by a spin code method, and the resin Light is irradiated onto the surface in a pattern through a photomask, and the exposed area is changed to be soluble in an alkaline aqueous solution, which is a developing solution, and removed by development to form a protective resin layer, or a heat- or photo-curable resin is used. is applied and formed in the same manner, and a master disk previously prepared using precision equipment such as a laser cutting machine is brought into close contact with this resin surface to transfer and form the groove pattern.
Next, cure the resin and protect the tree! There are methods of forming layers.

Furthermore, the exposed portions of the above-mentioned convex film are those that will eventually form track grooves. When the substrate is circular, the exposed shape is spiral or concentric, whereas in the case of a rectangular substrate, the exposed shape is linear, parallel to each other. Furthermore, in order to increase the track density, C/N ratio, etc., the width dimension of the exposed portion, which determines the width dimension T of the track groove, should be approximately equal to or less than the half width (Ω2) of the focused recording light spot.
Preferably, it is set to about Ω2/3 to 2×Ω2/3. On the other hand, the distance between each exposed part of the convex film that determines the track groove distance TP is set to 1/e2 full width of the recording focused light spot. When is Ωe, it is desirable to set it to approximately (T+Ωe)/2 in order to increase the track density. However, if the purpose is to reduce the internal stress of the recording layer and stabilize the recording performance, it is needless to say that the setting range is not limited to the above setting range. Furthermore, the thickness of the above-mentioned protective resin layer must be thick enough to remain and protect the convex film below during the etching process of the convex film in the convex formation process below. The depth dimension value varies depending on the type of protective resin layer used, the type of etching material, etc., but it is usually 5.
00 to 7000 angstroms, preferably 2000 angstroms
The thickness is set to about 5000 angstroms.

Next, the etching process in the above-mentioned protrusion forming step is to remove the exposed portion of the protrusion film to form protrusions for forming track grooves. CCI H1
Alternatively, a dry etching method using a gas based on CCl4 to which appropriate amounts of O, H, and N2 are added is suitable.

Next, the recording material in the recording film forming step is as follows:
All materials commonly known as optical recording materials can be used.

That is, Te, 5eSS, Sb, As, P.

Pb, Sn, Ge, Si, TI, In, Ga.

AI, Zn, AU, AQ, Cl, Pt, MOLTi
A single substance or a compound containing at least one component of elements such as , N + s Cr, and W, or a material in which these elements are dispersed in other materials can be used. Among these, Te and 5e-Te.

Pb-3e-Te, Te-C, etc. are non-rewritable recording/reproducing types. Hole drilling is suitable for shaped materials, and TeO, T
eax (Ge, Sn added), In-Se, In-8b
, In-Te1Sb2Se.

Te-Ge-8n, Te-Ge-8n-Au.

As S , 5b-Te1 Te-N, Ge-
Te.

Ag-1n, Ag-Zn, Cu-A I, Ag-Aj-
Cu, Cu-Al-N15Au-Ti, and Cr-Ti
etc. are suitable for phase change recording materials that are rewritable recording/reproducing/erasing type.

In addition, as rewritable magneto-optical recording materials, 1”e, C
o, N i , transition metals such as Mn, and Tb.

Gd, Nd, Pm, Sm, EnlDy, Ho, Er, T
Magnetic materials containing at least one component of rare earth elements such as m, Yb, Lu, etc., typically Tb-Fe-Co, T
I)=Fe, Dy-Fe.

Mn-Bi, Pt-Mn-8b, etc. can be applied.

In addition to the above materials, the recording layer may include organic dye materials such as cyanine dyes, phthalocyanine, naphthoquinone, squarylium, polythiophene, and polydiacetylene, and photochromic materials such as spiropyran, fulgide, and azobenzene. Available for use.

Further, as a means for forming a recording layer forming film having a substantially uniform thickness on the track groove formed by the above-mentioned convexity and the protective resin layer, for example, a vapor deposition method in which the above-mentioned recording material is directly formed, a sputtering method, etc. dry process can be applied. still,
When the affinity between the substrate and the recording material is weak, it is preferable to apply a base material having an affinity for the recording material onto the substrate in advance, if necessary.

Furthermore, in the recording layer forming step, the protective resin layer and the recording layer forming film formed on the upper surface of the protective resin layer are removed to expose the above-mentioned protrusions, and the recording layer forming film in the track grooves formed by the protrusions is removed. Methods for leaving the protective resin layer as a recording layer include an elution method using a solvent that dissolves the protective resin layer but does not dissolve the recording material, or a puff polishing method on the protective resin layer surface of the base material to remove the recording layer in areas other than the track grooves. A mechanical polishing method or the like for removing the formed film or the like is suitable, and an organic solvent such as acetone is suitable as a solvent for the above-mentioned elution method.

In addition, this technical means can be applied to a method of manufacturing an optical recording medium that has a recording layer on only one side, and can also be applied to a method of manufacturing an optical recording medium that has a recording layer on both sides. In this case, the latter can be formed by placing the recording layers facing each other and bonding two layers together using an adhesive or a spacer, and examples of this adhesive include urethane adhesives and epoxy adhesives. , curable silicone resin, hot melt adhesive such as ethylene-vinyl acetate resin, high frequency adhesive such as polyvinyl chloride resin, etc. can be used.

In addition, the light source used in the conventional method is used as a light source for recording/reproducing information or recording/reproducing/erasing information by irradiating focused light onto the recording layer of the optical recording medium obtained by this manufacturing method. Specifically, GaAlAs-based semiconductor lasers, GaA I InP-based semiconductor lasers, G
Semiconductor lasers such as a1nASP semiconductor lasers, He
Examples include gas lasers such as -Ne laser, Ar laser, and He-Cd laser.

Further, the optical recording medium manufactured according to the present invention can be applied to various uses such as optical discs for computers in addition to music recording media such as compact discs, and image recording media such as video desks.

[Function] According to the above-mentioned technical means, a film forming step of forming a 5-layer film on the substrate, and a resin forming a protective resin layer by exposing a part of the 5-layer film on the convex-layer film. layer forming process,
and 5. A track groove is formed on the substrate by a convex image forming step of etching the exposed portion of the film, and a recording layer forming film is provided in the track groove by a recording film forming step.
Furthermore, in the recording layer forming process, the protective resin layer and the recording layer forming film formed on the top surface of the protective resin layer are removed, making it possible to form the recording layer only within the track grooves with high precision and reliably. .

[Example] Hereinafter, an example in which the present invention is applied to an optical recording medium having a recording layer on one side will be described in detail with reference to the drawings.

First, a circular plate made of polymethyl methacrylate (10
), a 5-layer film (11) with a thickness of 1000 angstroms was formed by depositing Sio2 using a sputtering method, and then a photoresist material (manufactured by Hoechst, trade name AZ 1350J) was further deposited on this surface using a spin code method. ) to form a 3000 angstrom thick photoresist layer (12) (see Figures 1a-b).

Next, an excimer laser beam (wavelength: 2490 angstroms) using KrF was irradiated with a photomask (not shown) prepared by patterning the Cry film in close contact with the photoresist layer (12). , the photoresist layer (12) in the exposed area is changed in quality and made soluble in an alkaline aqueous solution as a developer, and the exposed area is dissolved and removed by the alkaline aqueous solution to form a film with a width T of 500 angstroms and a depth of about 3000 angstroms. - form a track pattern (see FIG. 1C).

Next, using the photoresist II (12) provided on the surface of the layer 5 coating (11) as a mask, the exposed surface of the layer 5 coating (11) was etched by a dry etching method using CF4 as an etching gas. , a substrate (2) having track grooves (3) formed with track-shaped protrusions (13);
) (see Figure 1C).

Then, 30
A TeoxWI layer (14) with a thickness of 0 angstroms is uniformly formed by vapor deposition (see FIG. 1C).

The thickness of this thin layer (14) varies depending on the type of recording material, but is usually set to about 100 to 2000 angstroms. Further, if the affinity between the plate material (10) surface and the recording material is weak, it is preferable to apply a base material on the plate material (10) surface as necessary.

Then, the photoresist 1id (12) remaining on the convex surface (13) is dissolved with an organic solvent such as acetone,
As shown in FIG. 1(f), the photoresist layer (12) and the Teox formed on the photoresist layer (12)
While removing the WX layer (14), the track groove (3)
After leaving the inner TeOx thin layer (14) as a recording layer (4), SiO2 is deposited on the surface of the substrate (2) on the recording layer (4) side.
11JI (5) consisting of
As shown in Figure (C)) and Figure 2, an optical recording medium (1) having a recording layer (4) only in the track groove (3) was manufactured.

[Effects of the Invention] According to the present invention, in the film forming step of forming a film for 5 conditions on a substrate, a part of the film for convex conditions is exposed and protected.
A track groove is formed on the substrate through a resin layer forming step of forming a resin layer and a convex image forming step of etching the exposed portion of the film for section 5, and a recording layer forming film is formed in the track groove by a recording film forming step. Further, in the recording layer forming step, the protective resin layer and the recording layer forming film formed on the upper surface of the protective resin layer are removed, and the recording layer is formed only within the track groove with high precision.
Moreover, it becomes possible to form the recording layer reliably.

Therefore, it is possible to easily and efficiently manufacture an optical recording medium having a recording layer only within the track groove.

[Brief explanation of the drawing]

1 to 2 show an embodiment of the present invention, FIGS. 1(a) to 2(Q) are process explanatory diagrams showing the manufacturing process of an optical recording medium according to this embodiment, and FIG. This is a partially sectional perspective view of this optical recording medium, and FIGS. 3 to 13 show conventional optical recording media, and FIG. 3 is a perspective view thereof, and FIG.
Figure 7 and Figure 7 are partial cross-sectional perspective views, Figure 5 is the illuminance distribution of a light source such as a semiconductor laser and the illuminance distribution of its convergent light spot, Figure 6 is an enlarged view of a portion of Figure 5, and Figure 8 is An explanatory diagram of the optical recording medium during playback, FIG. 9(a) is a partial cross-sectional view of the optical recording medium, FIG. 9(b) is a partial plan view thereof,
Figure 9(C) is the illuminance distribution of the recording and reproducing semiconductor laser spots, Figure 9(d) is a partial plan view of the optical recording medium when the track pitch is minimized, and Figures 10 to 12 are the tracks , a plan view showing the shapes of the recording layer and the recording dots,
FIG. 13 is an explanatory diagram showing internal stress applied to the recording layer;
14 to 20 show other conventional optical recording media, FIG. 14 is a partial cross-sectional perspective view of this optical recording medium, and FIG. 15 (a) is a partial cross-sectional view of this optical recording medium. 15(b) is a partial plan view of the optical recording medium, FIG. 15(C) is the illuminance distribution of the recording and reproducing semiconductor laser spot, and FIG. 15(d) is the optical recording medium when the track pitch is minimized. FIG. 16, FIG. 18, and FIG. 20 are partial plan views showing the shapes of track grooves, recording layers, and recording dots;
19 shows a relationship diagram between the reproduced signal level and time, and FIG. 19 shows a relationship diagram showing the relationship between the carrier signal level and noise signal level in the reproduced signal. [Explanation of symbols] (1)...Optical recording medium (2)...Substrate (3)...Track groove (4)...Recording layer (5)...Protective layer Patent Applicant: Fuji Xerox Co., Ltd. Representative Patent Attorney Tomohiro Nakamura (3 others) Figure 1 Figure 2 Figure 3 P'6 P'1 Figure 4 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Reproduction signal time

Claims (4)

[Claims] (1) An optical recording medium that optically records, reproduces, or erases information by irradiating it with focused light, including a substrate, and track grooves formed at a plurality of intervals on at least one surface of the substrate; In the method of manufacturing an optical recording medium having a recording layer formed in the track groove, a film forming step of forming a convex film on the substrate, a film forming step for protecting the convex film on the convex film; a resin layer forming step in which a protective resin layer is formed with the convex film partially exposed; a convex step in which the exposed portion of the convex film is etched to form a convex for forming track grooves; a forming step, a recording film forming step of forming a recording layer forming film on the track groove formed by the convexity and the protective resin layer, and removing the protective resin layer and the recording layer forming film formed on the upper surface thereof. an optical recording layer forming step of exposing the convexity and leaving a recording layer forming film in the track groove formed by the convexity as a recording layer. Method of manufacturing media. (2) The method for manufacturing an optical recording medium according to claim 1, wherein the recording film forming step is performed by a recording material vapor deposition method. (3) The method for manufacturing an optical recording medium according to claim 1, wherein the recording film forming step is performed by sputtering a recording material. (4) The method for manufacturing an optical recording medium according to claim 1, wherein the recording layer forming step is performed by an elution method in which the protective resin layer is eluted with a solvent that does not dissolve the recording material. .