JPS61151852A - Optical disk recording carrier - Google Patents

Abstract

PURPOSE:To improve the transcription properties in an injection molding or injection compression molding mode by setting the ratio between the width of an address bit and a tracking pitch at 1/8-1/4. CONSTITUTION:An optical disk is produced by coating a phase transfer type recording films, e.g., Sb2Se3 and Bi films which absorb the laser light to change their optical characteristics including the reflection factor, the transmittance, the diffractive index, etc. on the surface of a plastic substrate 3 of acrylic substance, polycarbonate, etc. containing an address bit 1 having the depth of 1/8 wavelength of the semiconductor laser light for record/reproduction and a guide groove 2. The ratio W/P between the width W of the bit 1 and the groove 2 and the track pitch P is set at 1/8-1/4. As a result, the transcription properties of the address bit are improved in an injection molding or injection compression molding mode. Furthermore the level of an address reproduction signal level is also raised up to secure the accurate demodulation of an address.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to reflective and transmissive video discs, digital discs, combination discs, memory discs, etc.
The present invention relates to an optical disc recording carrier for use in an optical disc recording and reproducing device capable of recording, searching and reproducing %Kfilf information at a high degree.

[Background of the invention]

A conventional optical disc of this kind is disclosed in Japanese Patent Application Laid-Open No. 1023-1983.
As described in No. 47, an address in which an address signal is written and a guide groove for tracking are formed on the board in advance, and this! l! These depths are set to approximately '/alfc of the wavelength of the light used for recording and reproducing, for ease of disc production. In addition, the width of the guide groove of the address pit is equal to the common width, and when high density and high C/N (carrier signal-to-noise ratio) are required, such as in video discs, the width is set to approximately [lL8μ island, and its track pitch is 2μm]. # is set after.

One way to create such an optical disc is to record address pits and guide grooves by irradiating a glass J
A molding stamper (mold) is created by performing fCNi plating, and a nine-leg substrate with addresses, grooves, and guide grooves is created using injection molding or injection compression molding, and a method such as vapor deposition is applied to this surface. There is a method in which a desired optical disc is manufactured by forming a recording film using the optical disc. Among these methods, the injection molding method or the injection compression molding method is excellent in mass production of leg-9-force substrates and is an advantageous method for reducing the cost of optical discs, but the molding material flows at high speed on the stamper type surface and In order to assimilate the new generation, the flow resistance is thicker in the discontinuous part like the address pit (5K), which is 17m in the evening direction, and the continuous part like the guide groove (to ensure uniform transferability to the replica board) It is not easy to do this.If the address pit @W, trackbi, and fPQ ratio W/P are close to each other or higher than this at t#, the transferability of the address pit will be poor). Unable to get address signal. The above-mentioned conventional technology did not take these problems into consideration.

[Purpose of the invention]

The purpose of the invention is to improve the shortcomings of the prior art, and to solve the problems as described above. It is an object of the present invention to provide an optical disc recording carrier that can record and reproduce data at high C/N and has excellent optical disc productivity.

[Summary of the invention]

The present invention provides an optical disc record carrier having address pits corresponding to address signals and guide grooves for tracking during recording, reproduction, and searching on a substrate.

It is characterized in that the ratio W/P of the width W of the front side and the tracking width W of the front side and the tracking side P of the front side is set to I~/k, thereby improving the transferability during injection molding or injection compression molding.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment FIGS. 1 and 2 are a sectional view and a partial plan view of the vicinity of an address via 1 of an optical disk according to the present invention. This optical disk is prepared in advance by an address pit 1 having a depth of R length (λ=a3-4/2) of semiconductor radar light for recording/reproduction.
A phase change type recording film that absorbs the laser beam and changes its optical properties such as reflectance, transmittance, refraction, etc. is placed on the surface of the substrate 3 made of plastic such as axyl or polycarbonate that has the guide WII 2. For example, a two-layer film of 8bz8es and Bi is deposited], and in particular, the width of the address pit and guide groove Wt-CL is 4μ.
Assuming a 6μ crow, the ratio 5 is set to 3. The method for making such a plastic substrate is as described above. First, a photoresist film corresponding to the depth of the address pits is formed on a glass substrate, and then the address pits and guide pins are formed on this.
A glass master disk is created by irradiating a finely focused alevon laser beam whose intensity is modulated with a signal corresponding to 1 m, and developing it. At this time, change the power of the argon laser to #
Address pits and guide grooves by adjusting
I can do it, Honji N! In 1fIJ, the groove width was adjusted to α4μjKill for Tora, Kubi, and Tet6μs. Next, this master was plated with Ni to form a Ni stamper having a thickness of α3μ, and this was used for injection molding to obtain a desired plastic substrate. Like this
The obtained optical disk is rotated at 1800 revolutions per minute, and the semiconductor laser beam is focused and irradiated onto the recording film using a lens with a numerical aperture (N, A,) of 0.6 to record information. As shown in the figure, a region 5 where the reflectance is locally high (f', width .alpha.8 .mu.m) is formed on the guide plate, and recording is completed. When such an optical disc is played back, the result shown in Figure 3 (
a) Reproduction signal shaping of the address and f'iv information as shown in Figure 10 can be obtained, and the address can be demodulated accurately. The average frequency of the address signal at this time is approximately 2 f'1liz. On the other hand, in the conventional technology, the width of the address pit and the guide groove is set to 18 μm, which is equal to the width of the address pit and the width of the guide groove. Figure 3 (b) Address as shown at point B.

As shown by the reduced production in Figure (a), address reproduction and signal waveforms become distorted, making it difficult to perform good address demodulation. Also, as in this actual example, KW/
When the P value is set as the name, as shown in Figure 'g4, the address at the time of playback and the reflected ray & Ir of Toya are W/P ≥ 3.
In other words, it is possible to increase the amplitude of the address reproduction signal as shown in FIG. 3(a). It can be seen that address demodulation is advantageous. Here, FIG. 4 shows values in which the amount of reflected light iIr and the maximum amplitude of the tracking d4 difference signal are normalized by their respective maximum values with respect to the address pit width W and the ratio W/P of tiger, crack, and chip P. From Figure 4, W
When /P='A, the maximum amplitude Itr of the relative tracking error signal decreases somewhat to W/P=4, but there is no problem in practical use. Furthermore, even if the W/P is lowered to A and the rtr is reduced to about α5, it is possible to obtain sufficient tracking characteristics by adjusting g4 of the optical tracking characteristics.

Furthermore, recording and playback performance in the case of W/P work/ is 1ff! Regarding Ic, K as shown in Figure 3 (4).

In the case of W/P-'/a, since there is a side surface of the guide groove in the center of W/P-'/a and the effective area of reflectance change decreases, vv/P= as shown in Fig. 5(a) 12. 1 if 8
The playback level is slightly lower than 3. However, if a film such as the 8bzSes and Bi Nino fI film used in this example, which can obtain a high C/N, is used, this will not pose a big problem in practice.

As described above, by adjusting the ratio vv7p of the width W of the address pit and guide groove to the track pitch yfP), the transferability of the address pit in injection molding or injection compression molding is improved, and , the address reproduction signal level also becomes high and accurate address demodulation becomes possible.
According to the present invention, the manufacturing yield of high-density, high-C/N optical disks can be significantly improved.

Example 2 In Example 1, as shown in FIG.
By increasing the width of the address pit so that the information bit does not protrude outside the guide groove, fi%
This makes it possible to prevent the reproduction level of information bits from decreasing as shown in FIG. 85 (4). In this case, when the address pit is busy, W/P = %, and good transferability can be obtained even if injection molding is used, and since one guide groove is a continuous tile, W/P = λ or more. Even if the transferability changes, the transferability does not change locally, and even if the overall uniform transferability changes somewhat, it does not pose a practical problem. To form a plastic substrate having address pits and guide grooves as shown in FIG. 5, when creating the glass master disk described in Example 1, adjust the argon laser power as shown in FIG. The photoresist on the substrate may be exposed and developed. That is, when recording an address, the argon laser power is set to P2, which is the same as in Example 1, and the width α4 μm is set.
When forming the grooves and recording the guide grooves, turn the power to P2.
Set a larger PIK and set the width α4μ or more, for example [L
Forms the SI horse groove. After creating the glass master, a plastic substrate is created using the injection molding method in the same manner as in Example 1, and a similar recording film is formed on this to obtain an optical disc.

As described above, according to this embodiment, an optical disc having address pits with good transferability and guide grooves with which a high level of information reproduction can be obtained can be manufactured by using the highly productive injection molding method or injection compression molding method. It becomes possible to manufacture.

Example & In Example 1 and Example 2, instead of using a phase-transition recording film, as shown in FIG. 7, the film was irradiated with semiconductor laser light to locally evaporate the film. It is clear that the hole-drilling method for recording [ as a hole has exactly the same effect as the above embodiment even if a type of recording film is used. In this case, the minimum level of the reproduced signal of the address pit and the maximum value of the reproduced signal of the information bit are the same, but by switching the reference levels of the address pit part and the guide groove part when these signals are detected, the signal can be changed. All can be detected.

Furthermore, the present invention can also be applied to the case where, instead of forming the hole in the mold recording process, the M7XIIc minute bulge is generated during laser beam irradiation to reduce the amount of reflected light at this part and record this as a clearing bit. Effects similar to those of the above embodiment can be obtained.

In the above embodiment, an optical disc having a recordable recording film was described, but this rlillKTe-8n-8
The present invention can also be applied to erasable optical discs using phase change type recording films capable of recording, reproducing, and erasing, such as 5b-8s-Bi, TeOx-8n-Ge, etc.
, furthermore, Co-Qd-Tb, Fe-Co-Tb,
The present invention #i can also be used for magneto-optical disks that use recording films such as Pe-Qd-'I'b and Fe-Gd-Tb- and require address pits and guide grooves similar to those of the above embodiments. ′
41: Compatible with the above example and I'! It will be clear that it has a t1-like effect.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to improve the transferability of address pits during injection molding or injection compression molding of optical disk substrates, and furthermore, it is possible to increase the address reproduction signal level, resulting in good address demodulation performance and high efficiency. , AiC/N
It is now possible to mass produce optical discs with
This will have a significant effect on reducing the cost of optical discs.

[Brief explanation of drawings]

Fig. 1 is a 11Jr plane view of the optical disc record carrier according to the present invention, Fig. 2 is a partial plan view of Fig. 1, and Fig. 3 (^) and lb) shows the relationship between optical disc reproduction signal formation and distortion and transferability. Explanatory diagram, Figure 4 shows the W/P, the total radiation beam cover, and the maximum tracking error signal! IIQ! FIG. 5 is a partial plan view of the second embodiment of the present invention, and FIG.
The figure shows the relationship between the exposure intensity of the address pit portion and the guide groove portion, and FIG. 7 is a cross-sectional view of the third embodiment of the present invention. 1...address pit 2...guide groove 3...substrate 4...recording film 5...information and Chair (b) 0 In Le W/P Fig. 4 w/P Foil 7 Fig.

Claims (1)

[Claims] 1. In an optical disc record carrier having address pits corresponding to address signals and guide grooves for tracking in recording, reproduction, and retrieval on a substrate, the ratio W of the width W of the address pits to the track pitch P. /P to 1/
An optical disc record carrier characterized in that the size is 5 to 1/4. 2. The optical disc record carrier according to claim 1, wherein the width of the guide groove is larger than the width of the address pit.