JPH01315032A - Optical information recording medium and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an optical information recording system in which prepits longer than the diameter of a radiation spot for reproduction and prepits shorter than the diameter of the radiation spot for reproduction are formed in a mixed manner. The present invention relates to a medium and its manufacturing method.

[Conventional technology]

2. Description of the Related Art Write-once or rewritable optical information recording media in which pre-pit rows and pre-grooves are formed in advance in a recording area are conventionally known. Pre-pit rows and pre-grooves are recorded in the form of unevenness on the surface of the substrate, and a reproduction radiation spot with a diameter larger than the width of these pre-pits and pre-grooves is irradiated, and the intensity of the reflected or transmitted light is optically detected. The signal can be read out optically by detecting it with a device.

In other words, in the area where there are pre-pits, light interference and diffraction occur between the light irradiated to the pre-pits themselves and the light irradiated to the land portion (the area where pre-pits 1 and no pre-grooves are formed). The intensity of light incident on the photodetector decreases, and since these phenomena do not occur in areas where there are no pre-pits, the intensity of light incident on the photodetector increases.

Therefore, the pre-pit signal can be read out from the output signal waveform of the photodetector.

In order to facilitate signal readout, it is preferable that the reproduction signal level, that is, the difference in the intensity of light incident on the photodetector between the part with pre-pits and the part without pre-pits, be as large as possible.

The intensity of light incident on the photodetector from the portion where the prepits are located is related to the size of the prepits. The refractive index of the substrate is n
l, the refractive index of air is nz, the wavelength of the reproduction radiation is λ, and the diameter of the reproduction radiation spot is φ.In the reflective optical information recording medium, the depth (or richness) of prepits is d. =N・λ/4nz (however, N is a positive odd number),
When the width of the pre-pit is φ/3, the intensity of light incident on the photodetector is minimized. In addition, in a transmissive optical information recording medium, the depth (or height) d of prepits is d=N・λ
/4(nl-nz), and the intensity of reflected light to the photodetector is minimized when the pre-pit width is φ/3 ("optical memory").
, Magneto-Optical Memory Comprehensive Technology Collection”, Science Forum Co., Ltd., published October 31, 1980, pp. 29-
p. 30).

By the way, when manufacturing this type of optical information recording medium,
First, a signal-modulated cutting light is irradiated onto a master disc on which a photoresist layer is formed to cut grooves that will become the basis of the pre-pits and pre-grooves, and then an inverted pattern of the grooves is transferred from this master disc to a substrate. method is adopted.

The size of the groove (pre-pit) that can be cut into the photoresist layer is proportional to the product of the cutting light intensity and irradiation time. Therefore, when long pre-pits and short pre-pits are cut with cutting light of a constant intensity, the size of the long prepits becomes large, and the size of short prepits becomes small.

Therefore, if the width of either the long prepit or the short prepit is set to the above-mentioned optimal value, the width of the other prepit will become inappropriate.
In either case, proper recording and reproduction of information is hindered.

In particular, if the width of the long pre-pits is set to the above-mentioned optimum value, the playback output level from the short pre-pits will be extremely low, making it impossible to meet the demand for improving recording density by shortening the overall pit length. .

In order to eliminate such inconvenience, the applicant first proposed the following:
We proposed an optical information recording disk characterized in that the width of the pits, which are shorter than the diameter of the laser spot for reproduction, is larger than the width of the pits, which are longer than the diameter of the laser spot for reproduction. -214149).

As a manufacturing method for such an optical information recording disk, the optical disk master is rotated at a constant angular velocity, and in the outer peripheral area where the pit length of the minimum pit is longer than the diameter of the reproduction laser spot, the rotation of the optical disk master is The photosensitive surface of the optical disk master is exposed with an exposure intensity proportional to the distance from the center to the center of the laser spot for cutting. Furthermore, in the inner peripheral region where the pit length of the minimum pit is shorter than the diameter of the reproduction laser spot, the photosensitive surface is exposed with the same exposure amount as the pits in the region where the pit length is longer than the diameter of the reproduction laser spot. He proposed a method to make it possible.

According to this method, pre-pits with short pit lengths are formed wide, so that the reproduced output signal level does not decrease. Therefore, the signal length of the recording signal can be shortened, the recording density can be increased, the recording capacity can be increased, and the diameter of the optical information recording disk can be reduced.

[The burden that the invention attempts to solve]

The optimum value of the pre-pit size described above is for an optical information recording medium that uses an in-group recording method or does not have a pre-groove, and in which the track pitch is adjusted so that the reproduction radiation spot does not fall on adjacent tracks. The theory applies.

However, in optical information recording media such as on-land recording type optical information recording media or optical information recording media with a narrow track pitch, the peripheral edge of the radiation spot for reproduction overlaps the adjacent track of the track from which the signal is to be reproduced. , when the width W of the pre-pit is formed to the above-mentioned optimum value, the amount of light irradiated to the land part is reduced by the amount that the peripheral part of the reproduction radiation spot covers the adjacent track, and the light interference effect is reduced, so that the photodetector The intensity of the incident light increases. Therefore, for prepits shorter than the diameter of the radiation spot for reproduction, the reproduction output level decreases, and for prepits longer than the diameter of the radiation spot for reproduction, distortion 42 is generated in the reproduction signal waveform 41 as shown in FIG. do.

In addition, the pre-pit rows include long and short pit lengths, but if the width of the pre-pits, which is longer than the diameter of the radiation spot for reproduction, is formed to the above-mentioned optimum value, the resin used when injection molding the substrate There are interlayers that impede the flow of pre-pits and deteriorate the transferability of pre-pits.

In order to eliminate this inconvenience, as shown in Figure 10,
An optical information recording medium has been proposed in which the leading end 43a and the trailing end 43b of the pre-pits 43 are tapered. However, if the shape of the pre-pits 43 is formed as shown in FIG. 10, although it is effective in eliminating waveform distortion, the reproduced signal level L becomes small as shown by the dashed line in FIG. 9, resulting in signal readout errors. becomes more likely to occur.

On the other hand, in the manufacturing method of an optical information recording disk previously proposed by the applicant, a ring-shaped recording area is circumferentially divided into a large number of sectors, and each sector of each recording track is divided into sectors. It has been found that the following drawbacks are found in the production of pre-formed ID pits such as sector mark pits indicating divisions, address pits, and synchronization pits.

That is, the sector mark pit is formed longer than the ID pit in order to prevent confusion with the ID pit.

For example, if the time length of an address signal read from an optical information recording disk rotated at 1800 rpm and the period of a synchronization pit signal are 90 nsec, the sector mark is formed to have a length of 540 nsec or 900 nsec.

If each pre-pit is formed to such a length, even in areas where the ID pit is shorter than the diameter of the radiation spot for reproduction, the sector mark will be longer than the diameter of the radiation spot for reproduction, and the same sector of the same trunk Pits shorter than the diameter of the radiation spot for reproduction and pits longer than the diameter of the radiation spot for reproduction coexist within the area.

The conventional method described above for forming such a pre-pit pattern,
That is, if a method is adopted in which all prepits included in the same track are exposed with the same power, the size of the prepits formed as described above is proportional to the product of the power of the cutting radiation beam and its irradiation time. The long sector mark portion becomes overexposed, and the sector mark becomes wider than the ID pit.

In the above description, the sector mark is used as a pit longer than the diameter of the radiation spot for reproduction, and the ID pit 1-1 is used as a pit shorter than the diameter of the radiation spot for reproduction.
I explained this using an example, but regardless of the type of pre-pit,
A similar problem occurs in all cases where pits longer and shorter than the diameter of the reproduction radiation spot coexist.

Therefore, a first object of the present invention is to provide an optical information recording medium that does not cause a reduction in the reproduction output level or distortion in the reproduction signal waveform even if the peripheral portion of the radiation spot for reproduction touches an adjacent track.

A second object of the present invention is to provide a method for manufacturing such an optical information recording medium.

[Means to solve division problems]

In order to achieve the above-mentioned first object, the present invention has a recording area in which pre-pits longer than the diameter of the radiation spot for reproduction 1- and prepits shorter than the diameter of the radiation spot for reproduction are formed in a mixed manner. In the optical information recording medium, when the diameter of the radiation spot for reproduction is φ, the width W of the pre-pit is longer than the diameter φ of the radiation spot for reproduction.

φ/4<W<φ/3 was formed.

In addition, in order to achieve the above-mentioned second objective, when cutting an M disk having prepit rows, the radiation power when cutting prepits that are longer than the diameter of the radiation spot for reproduction is set to be lower than the diameter of the radiation spot for reproduction. The radiation power was also made smaller than that used when cutting short pre-pits.

[Effect]

For optical information recording media using on-land recording method.

As shown in FIG. 11(a), the reproduction radiation spot 4
The range in which the peripheral edge of the groove 5 is irradiated onto the adjacent pregroove 46 is sufficient to be within a range of 172 to 1 times the width S of the pregroove 46. In an in-group recording type optical information recording medium, if the 1-rack pitch is too narrow, signal crosstalk will occur, so as shown in FIG. 11(b),
The periphery of the reproduction radiation spot 45 is adjacent to the adjacent track 47
The track pitch is adjusted so that there is almost no difference between the

If the range in which the peripheral edge of the reproduction radiation spot 45 is irradiated onto the adjacent pregroove 46 is this range, and the intensity distribution within the reproduction radiation spot is a Gaussian distribution, the diameter of the reproduction radiation spot 45 If the width W of the prepit is longer than φ and is formed so that φ/4<W<φ/3,
The amount of radiation irradiated to the prepit portion and the amount of radiation irradiated to the land portion are balanced, the reproduction output level is maximized, and the distortion of the reproduction signal waveform is eliminated.

Further, by cutting each prepit according to the length of the prepit as described above, the width of all prepits can be optimized regardless of the length of the prepit.

〔Example〕

FIG. 1 shows a plan view of essential parts of an optical information recording medium according to the present invention.

In this figure, 1 is a substrate, 2 is a prepit row, 3 is a sector mark pit, 4 is an ID bit row, 5 is an address pit, 6 is a synchronization pit, 7 is a pregroove, and 8 is a reproduction radiation spot.

As shown in this figure, in the optical information recording medium of this embodiment, the sector mark pit 3 is located at the reproduction radiation spot 8.
, and all the address pits 5 and synchronization pits 6 included in the ID pit row 4 are formed shorter than the reproduction radiation spoilers 1 to 8.

The pre-groove 7 is formed to have a width S that is approximately equal to each of the pre-pits 3 and 5.6 described above, and its track pitch P is such that the peripheral edge of the radiation spoiler l-8 for reproduction is 1/1/2 of the width S of the pre-groove. It is set to irradiate in a range of 2 to 1 times.

The width Wl of the sector mark pit 3 is when the diameter of the reproduction radiation spot 8 is φ.

φ/4<W 1<φ/3 is formed.

The depth (or height) d of this sector mark pit 3 is
When the refractive index of the substrate is nl, the refractive index of air is n2, the wavelength of the reproduction radiation is λ, and the diameter of the reproduction radiation spot is φ, for a reflective optical information recording medium, d=N・λ/
4n] (where N is a positive odd number). Also,
For transmission type optical information recording media, d=N-λ/4(n
x n2).

On the other hand, the address bit 1- included in the ID bit string 4
The width W2 of the address pit 5 and the synchronization pit I-6 is formed to be Wz"φ/3. The depth (or height) of the address pit 5 and the synchronization pit I-6 is formed in the same manner as the sector mark pit 3 described above. be done.

Further, the depth (or depth) of the pre-groove 7 is the same as the pre-pit 3, 5. Equivalent to or shallower than G
(low) formed.

In the optical information recording medium of the above embodiment, the width W1 of the sector mark pit 3, which is formed to be longer than the diameter of the radiation spot for reproduction, satisfies φ/4 < W z <φ/3 (however, φ
is the diameter of the reproduction radiation spot), the reduction in light interference caused by the peripheral edge of the reproduction radiation spot 8 being exposed to the pregroove is corrected, and the reproduction signal level can be maintained at a high level. Furthermore, for the same reason, a reproduced signal without distortion can be obtained as shown in FIG. Therefore, sector marks are reliably detected and access errors are improved.

In addition, since the sector mark pit 3, which is longer than the diameter of the radiation spot for reproduction, is formed narrowly in this way, the flow of resin when injection molding the substrate is improved, and the transferability of pre-pits and pre-grooves is improved. Improved.

Furthermore, regarding the ID pit 4 formed shorter than the diameter of the radiation spot for reproduction, its width Wz is determined by Wz=φ/
3, the interference of light is not reduced even if the peripheral edge of the reproduction radiation spot 8 is in the pre-groove. Therefore, the reproduced signal level can be maintained at a high level, and distortion does not occur in the reproduced signal waveform.

In the above embodiment, the sector mark pit 3 is formed longer than the diameter φ of the reproduction radiation spot 8, and the address pit 5 and the synchronization pit 6 are formed shorter than the diameter φ of the reproduction radiation spot 8. As explained above, the length of the address pit 1-5 and the synchronization pit 6 is longer than the diameter φ of the regeneration radiation stub I-8.
: In case 1, the width of these pre-pits is also φ/4 <W
<φ/3.

Furthermore, in the above embodiments, an on-land recording type optical information recording medium has been described, but an in-group recording type optical information recording medium can also be formed in the same manner.

Further, the shape of the optical information recording medium according to the present invention is not limited to a disk shape, but can be formed into any arbitrary shape such as a card shape.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical disk master cutting apparatus applied to the present invention will be shown, and a method for manufacturing an optical information recording medium according to the present invention will be explained based on this.

FIG. 3 shows an apparatus applied to manufacturing an in-group recording type optical information recording medium, in which reference numeral 11 denotes an optical disk master, 1
2 is a turntable, 13 is an argon laser, 14 is a first optical modulation element, 15 is a reflecting mirror, 16 is a second optical modulation element, 17 is a formatter driver connected to the second optical modulation element 16, 18 and 19 are signal sources applied to the formatter driver 7, 20 is a reflecting mirror, 21 is a beam expander, and 22 is a helium 11-neon laser (
(hereinafter abbreviated as He-Ne laser), 23 is a half mirror, 124 is a beam mixing prism, 25 is a reflecting mirror, 26
is the cutting head, 27 is the cutting head 26
28 is an objective lens mounted on the cutting head 26, and 29 is a focus control circuit for the cutting head 26.

The argon laser 13 is used for exposing the photosensitive surface formed on the optical disk master 11, and the He-Ne laser 22, which has a wavelength outside the photosensitive range of this photosensitive surface, is used for automatic focusing of the focus actuator 27 provided in the cutting head 26. Used for adjustment.

As the optical modulation elements 14 and 16, any combination of acousto-optic modulation elements and electro-optic modulation elements can be used. The acousto-optic modulator is created by applying an alternating voltage to a piezoelectric material made of LiNb○, etc., and then
Ultrasonic waves (concentration waves) are generated in a medium made of bMo○4, etc., and this is used as a diffraction grating (i) to diffract multiple waves. Electro-optic modulators are designed to obtain modulated light.-On the other hand, an electro-optic modulator applies a voltage to a Pockels cell to create anisotropy between the main axis of the index ellipsoid of the crystal, and generates two beams traveling inside the crystal. It utilizes the phenomenon that causes a difference in phase velocity in linearly polarized waves that is proportional to the strength of the electric field, and the elliptically polarized light emitted from the Pockels cell is extracted through an analyzer to obtain amplitude-modulated exit light. It has become.

Therefore, by adjusting the voltage values applied to these optical modulation elements 14 and 16, the amount of exposure of the photosensitive surface formed on the optical disc original @11 can be adjusted as appropriate.

Note that the first optical modulation element 14 is provided for power adjustment and noise reduction of the laser beam incident on the second optical modulation element 16, and the second optical modulation element 16 is provided for the purpose of noise reduction. It is provided for signal modulating the laser beam incident from the element 14.

A signal source 18 applies data corresponding to the ID pit to the formatter driver 17, and a signal [19 applies data corresponding to the sector mark to the formatter driver 17.
7.

The formatter driver 17 inputs a signal at an optimum level to the second optical modulation element 16 according to the signal from the signal source 18-19.

As shown in FIG. 4, the input signal level of the second optical modulator 'P16 and the reproduction signal level from the pre-pits formed thereby are rjH! fJrA, for address pin 1- and synchronization pin 1-, the reproduced output signal level is maximum when the input signal level to the second optical modulation element 16 is set to 100%, and for the sector mark, the reproduction output signal level is maximum. When the input signal level to the optical modulation element 16 is set to 50 to 80%, the reproduced output signal level becomes maximum.

Therefore, from this formatter driver 17.

As shown in FIG. 5, a high-level signal H that maximizes the modulation efficiency of the second optical modulation element 16 is output in response to the ID signal, and a high-level signal H is output in response to the sector mark signal. A low level signal I- is output so that the modulation efficiency of the second optical modulation element 16 is 50 to 80%. In addition, the fifth
What is indicated by the symbol PG in the figure is a signal for pregroove cutting, which is adjusted to a signal level such that the modulation efficiency of the second acousto-optic element 16 is 20 to 35%.

The levels of the signals H, L, and PG at each level can be adjusted by passing the signals output from the signal sources 18 and 19 through an attenuator.

The sector mark signal is passed through an attenuator of 0.5 to 2 (dB), and the modulation efficiency of the second optical modulation element 16 is 50 to 2 (dB).
It is adjusted to 80%.

The signals whose levels have been adjusted as described above are combined at the same timing as shown in FIG. 5, and applied to the second optical modulation element 1G.

Figure 6 shows optical disk master cutting' which is applied to the production of on-land recording type optical information recording media! FIG. 3 is a diagram showing position A, in which the optical path from the first optical modulation element 14 to the objective lens 28 is divided into two, and a second optical modulation element 33 and a third optical modulation element are placed in each optical path 31 and 32. Optical modulation element 34
are set so that two beam spots are irradiated from the objective lens 28 at a predetermined interval in the radial direction of the optical disk master 11.

The second optical modulation element 33 includes a signal source (not shown) that outputs a sector mark signal and an ID signal, and a formatter driver (not shown) that adjusts the level and synthesis timing of each of these signals. connected via. The level adjustment means for the sector mark signal and the ID signal and their sizes are the same as those described in connection with the apparatus shown in FIG.

A signal shown in FIG. 7 is applied to the second optical modulation element 33. On the other hand, the third optical modulation element 34 is provided with a signal source (not shown) that outputs a pregroove signal at a constant level.
is connected.

The parts other than those described above are almost the same as the apparatus shown in FIG. 3, and the corresponding parts are denoted by the same reference numerals and the explanation thereof will be omitted.

When cutting an optical disk master using the cutting apparatus shown in FIGS. 3 and 6, the cutting head 2 is rotated at a constant angular speed by rotating the turntable 12 to rotate the unrecorded optical disk master 11 at a constant angular velocity.
6 is moved at a constant speed from the inner circumference to the outer circumference of the optical disk master 11, and a laser beam whose signal is modulated by the signal shown in FIG. 5 or FIG. 7 is irradiated from the objective lens 28.

Expose the photosensitive surface. Therefore, in the apparatus shown in FIG. 3, a single concavo-convex pattern in which the sector mark signal, ID signal, and pregroove signal are superimposed is cut in a spiral shape.

In addition, in the apparatus shown in FIG. 6, the pre-pit row in which the sector mark signal and the ID signal are superimposed and the pre-groove by the pre-groove signal are cut in a double spiral shape, and in the end, the prepit row is cut between the two pre-grooves. An on-land recording type optical disk master is formed, in which the images are arranged.

In this case, as shown in FIG. 8, as the distance from the rotation center of the optical disc master disk to the irradiation center of the laser spot increases, the laser power for cutting the sector mark pits and TD pits is gradually increased, and the laser spot and It is possible to correct a decrease in exposure intensity due to an increase in the relative speed to the photosensitive surface.

The optical information recording disc is pre-recorded as described above.
First, a mold called a stamper is created using a transfer technology from the master disc on which the rows are formed.

Next, the substrate onto which the pre-pit rows have been transferred from this stamper is duplicated, and a thin film layer such as a recording film is further provided on the signal surface of this substrate.

When the optical disc master is exposed in the above method, the laser power applied to the optical disc master is optimized according to the type (length) of the prepits, and the widths W x and W Z of each prepit formed after development are adjusted. It can be formed to a predetermined value.

The formatter driver 17 also has two signal sources 18.
19, the level of the sector mark signal and the level of the ID signal can be adjusted independently, making it easy to adjust the modulation efficiency.

The gist of the present invention is that the radiation power when cutting prepits longer than the diameter of the radiation spot for reproduction is made smaller than the radiation power when cutting prepits shorter than the diameter of the radiation spot for reproduction. However, the input A level to the cutting device and the optical modulation element is not limited to that listed in the above embodiment.

For example, in the embodiment described above, an argon laser was used as the light source, but the gist of the present invention is not limited thereto.

It can be selected from any radiation.

In addition, in the embodiment, the formatter driver 1
Although the case where the formatter driver 17 is provided with two signal sources 18 and 19 has been described, the gist of the present invention is not limited to this, and it is of course possible to control the formatter driver 17 with one signal source. .

Furthermore, in the above embodiment, a case was explained in which sector marks were exposed with a small exposure intensity and address pits and synchronization pits were exposed with a large exposure intensity. It can be applied to all cases where long pits and short pits coexist.

Further, the method of driving the optical disk master 11 during cutting is not limited to the constant angular velocity rotation method, and can be carried out in exactly the same manner even in the case of the constant angular velocity rotation method.

Furthermore, although the present invention is applicable to optical information recording disks of any size, it is particularly effective for disks of 5.25 inches or less, where the pit size is small. Further, there is no limitation on the type of optical information recording disk, and the present invention can be applied to any type of optical disk such as a video disk, a compact disk, or an optical disk memory for a computer.

〔Effect of the invention〕

As explained above, in the optical information recording medium of the present invention, the width W of the pre-pits is longer than the diameter φ of the radiation spot for reproduction.
1, φ/4<W l<φ/3, and the width Wz of the pre-pit, which is shorter than the diameter of the radiation spot for reproduction, is formed to φ/3, so the reproduction signal level is high and the reproduction signal is free from waveform distortion. can be obtained. Therefore, signal read errors are improved.

In addition, in the V5 manufacturing method of the optical information recording medium of the present invention, the laser power irradiated onto the master disc is adjusted according to the type (length) of the prepits, so the width of each prepit can be optimized. Can do 6

[Brief explanation of the drawing]

FIGS. 1 to 8 are diagrams of embodiments of the present invention.
The figure is a plan view of essential parts of the optical information recording medium according to the present invention, Figure 2 is a graph diagram showing the effects of the present invention, and Figure 3 is an example of an optical disk master cutting device applied to the implementation of the present invention. The optical circuit diagram, Fig. 4 is a graph showing the relationship between the input (No. 8 level) of the optical modulation element and the level of the reproduced signal read out from the formed BRIPIT 1~, and Fig. 5 is the graph showing the relationship between the input level of the optical modulation element (No. 6 is an optical circuit diagram showing another example of the optical disk master cutting device applied to the implementation of the present invention, and FIG. 7 is a graph showing another pattern of the signal input to the optical modulation element. Graph diagram showing examples,
FIG. 8 is a graph showing the relationship between the distance from the rotation center of the optical disk master to the irradiation center of the radiation spot and the radiation power irradiated to the optical disk master. FIGS. 9 to 11 are diagrams showing the prior art, in which FIG. 9 is a graph diagram showing problems in the prior art, FIG. 10 is a plan view of the main part showing the pre-pit shape that was previously conceived, 11th
Figures (a) and (b) are explanatory diagrams of the on-land recording method and the in-group recording method. ■ = Substrate, 2: Bull bit row, 3: Sector mark bit, 4: ID pit row, 5 Near address h, 6: Sync pit, 7: Pregroove, 8: Reproduction radiation spot l-
, 1.1: Optical disc master, 12: Turntable, 1
4.16: Optical modulation element, 17: Formator driver, 18, 19: Signal source, 18: Objective lens, Figure 2 Yotankai Figure 3 11: Optical Denos 7 & Temporary 17 ;7 Oh?・To ivy dry'I3: Argon dry
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Claims (13)

[Claims] (1) In an optical information recording medium formed by a mixture of prepits longer than the diameter of the radiation spot for reproduction and prepits shorter than the diameter of the radiation spot for reproduction, when the diameter of the radiation spot for reproduction is φ , the width W of the pre-pit is longer than the diameter φ of this radiation spot for reproduction.
An optical information recording medium characterized in that φ/4<W<φ/3. (2) In the optical information recording medium according to claim (1), the sector mark pit is formed with prepits that are longer than the diameter φ of the reproduction radiation spot, and are shorter than the diameter φ of the reproduction radiation spot. An optical information recording medium characterized in that ID pits including at least synchronization pits and address pits are formed with pre-pits. (3) The optical information recording medium according to claim (1), wherein each pre-pit is formed overlapping a pre-groove. (4) The optical information recording medium according to claim (1), wherein each pre-pit is formed between two adjacent pre-grooves. (5) In the optical information recording medium according to claim (1), the outer shape of the optical information recording medium is formed into a disk shape, and the pre-pits and pre-grooves are formed in a spiral shape or a concentric circle concentric with the center of the optical information recording medium. An optical information recording medium characterized by being formed in. (6) In the optical information recording medium according to claim (1), the outer shape of the optical information recording medium is formed into a card shape, and the pre-pits and pre-grooves are formed in the form of parallel lines extending parallel to the sides of the optical information recording medium. An optical information recording medium characterized by being formed in. (7) A method for manufacturing an optical information recording medium including the step of intermittently irradiating a master with a radiation beam and cutting a prepit row consisting of a combination of a plurality of prepits with different lengths for each sector, Among the plurality of prepits to be formed, the radiation power when cutting the prepits longer than the diameter of the reproduction radiation spot is made smaller than the radiation power when cutting the prepits shorter than the diameter of the reproduction radiation spot,
A method for manufacturing an optical information recording medium, characterized in that the width of the prepits, which is longer than the diameter of the radiation spot for reproduction, is equal to or narrower than the width of the prepits, which are shorter than the diameter of the radiation spot for reproduction. (8) In the method for manufacturing an optical information recording medium according to claim (7), a signal corresponding to a prepit longer than the diameter of the radiation spot is added to the optical modulation element that modulates the radiation beam emitted from the light source; By connecting a format driver that can independently apply a signal corresponding to the prepits shorter than the diameter of the radiation spot for reproduction, the radiation power when cutting a prepit longer than the diameter of the radiation spot for reproduction and the width of the radiation spot for reproduction can be adjusted. A method for manufacturing an optical information recording medium, characterized in that radiation power and radiation power when cutting a prepits shorter than its diameter are independently adjusted. (9) In the method for manufacturing an optical information recording medium according to claim (8), when cutting the prepits shorter than the diameter of the reproduction radiation spot, the modulation efficiency of the optical modulation element is maximized. When cutting a pre-pit longer than the diameter of the radiation spot for reproduction, adjust the input signal level of the optical modulation element so that the modulation efficiency of the optical modulation element is 50% to 80%. 1. A method for manufacturing an optical information recording disc, characterized in that the input signal level of the disc is adjusted. (10) In the method for manufacturing an optical information recording medium according to claim (7), a formatter driver including an attenuator of 0.5 to 2 decibels in an optical modulation element that modulates a signal on the radiation beam emitted from the light source. A signal corresponding to a prepit longer than the diameter of the radiation spot for reproduction is passed through the attenuator, and the output signal is combined with a signal corresponding to a prepit shorter than the diameter of the radiation spot for reproduction to generate the optical signal. A method of manufacturing an optical information recording medium, characterized in that the voltage is applied to a modulation element. (11) In the method for manufacturing an optical information recording medium according to claim (7), the sector mark pit is formed with prepits longer than the diameter of the reproduction radiation spot, and the sector mark pit is longer than the diameter of the reproduction radiation spot. A method for manufacturing an optical information recording medium, characterized in that ID pits are formed with short prepits. (12) In the method for manufacturing an optical information recording medium according to claim (7), the disk-shaped master is rotated at a constant angular velocity, and the radiation power for cutting the pre-pit row is applied to the rotation center of the master. A method for manufacturing an optical information recording medium, characterized in that the distance is adjusted according to the distance from the irradiation center of the radiation spot to the irradiation center of the radiation spot. (13) The method for manufacturing an optical information recording medium according to claim (12), characterized in that the recording area of the master disc into which the pre-pit row is cut is 5.25 inches or less. .